Add README back to SystemTests

Add back the README that describes the various tests
in cime/utils/python/CIME/SystemTests.  Point to the
old directory where some tests remain.

utils/python/CIME/SystemTests/README

@@ -0,0 +1,134 @@
+The following are the test functionality categories:
+  1) smoke tests
+  2) restart tests
+  3) threading/pe-count modification tests
+  4) sequencing (layout) modification tests
+  5) multi-instance tests
+  6) performance tests
+  7) spinup tests (TODO)
+
+Some tests not yet implemented in python.  They can be found in
+cime/scripts/Testing/Testcases
+
+
+NOTES: 
+- IOP is currently not functional
+
+======================================================================
+    Smoke Tests
+======================================================================
+
+SMS    smoke startup test (default length) 
+       do a 5 day initial test (suffix: base)
+       if $IOP_ON is set then suffix is base_iop
+       success for non-iop is just a successful coupler 
+
+======================================================================
+    Restart Tests
+======================================================================
+
+ERS    exact restart from startup (default 6 days + 5 days) 
+       do an 11 day initial test - write a restart at day 6     (suffix: base)
+       if $IOP_ON is set then suffix is base_iop
+       do a  5  day restart test starting from restart at day 6 (suffix: rest)
+       if $IOP_ON is set then suffix is rest_iop
+       compare component history files ".base" and ".rest" at day 11 
+
+ERP    pes counts hybrid (open-MP/MPI) restart bfb test from startup, default 6 days + 5 days (previousy PER)
+       initial pes set up out of the box
+       do an 11 day initial test - write a restart at day 6     (suffix base) 
+       half the number of tasks and threads for each component
+       do a  5  day restart test starting from restart at day 6 (suffix rest)
+       this is just like an ERS test but the pe-counts/threading count are modified on retart
+
+ERI    hybrid/branch/exact restart test, default (by default STOP_N is 22 days)
+       (1) ref1case
+           do an initial for ${STOP_N}/6 writing restarts at ${STOP_N}/6
+           ref1 case is a clone of the main case (by default this will be 4 days)
+           short term archiving is on
+       (2) ref2case
+           do a hybrid for ${STOP_N}-${STOP_N}/6 running with ref1 restarts from ${STOP_N}/6
+           and writing restarts at ( ${STOP_N} - ${STOP_N}/6 )/2 +1 
+	   (by default will run for 18 days and write a restart after 10 days)
+           ref2 case is a clone of the main case 
+           short term archiving is on
+       (3) case 
+           do a branch run starting from restart written in ref2 case 	   
+           and run for ???  days
+       (4) case do a restart run from the branch case
+
+ERT  Similar to ERS but longer.  2 months + 1 month
+
+
+======================================================================
+    Restart and Archive Tests
+======================================================================
+ERR
+
+
+======================================================================
+    Threading/PE-Counts/Pe-Sequencing Tests
+======================================================================
+
+PET    modified threading openmp bfb test (seq tests)
+       do an initial run where all components are threaded by default (suffix: base)
+       do another initial run with nthrds=1 for all components        (suffix: single_thread)
+       compare base and single_thread
+
+PEM    modified pe counts mpi bfb test (seq tests)
+       do an initial run with default pe layout                               (suffix: base)
+       do another initial run with modified pes (NTASKS_XXX => NTASKS_XXX/2)  (suffix: modpes)
+       compare base and single_thread
+
+PEA    single pe bfb test 
+       do an initial run on 1 pe with mpi     (suffix: base)
+       do the same run on 1 pe with mpiserial (suffix: mpiserial)
+
+======================================================================
+    Sequencing (layout) Tests (smoke)
+======================================================================
+
+SEQ    different sequencing bfb test  
+       do an initial run test with out-of-box PE-layout (suffix: base)
+       do a second run where all root pes are at pe-0   (suffix: seq)
+       compare base and seq
+
+======================================================================
+    Multi-Instance Tests (smoke)
+======================================================================
+
+NCK    multi-instance validation vs single instance - sequential PE for instances (default length)
+       do an initial run test with NINST 1 (suffix: base)
+       do an initial run test with NINST 2 (suffix: multiinst for both _0001 and _0002)
+       compare base and _0001 and _0002
+
+NCR    multi-instance validation vs single instance - concurrent PE for instances  (default length)
+       do an initial run test with NINST 1 (suffix: base)
+       do an initial run test with NINST 2 (suffix: multiinst for both _0001 and _0002)
+        compare base and _0001 and _0002
+       (***note that NCR_script and NCK_script are the same - but NCR_build.csh and NCK_build.csh are different***)
+
+NOC    multi-instance validation for single instance ocean (default length)
+       do an initial run test with NINST 2 (other than ocn), with mod to instance 1 (suffix: inst1_base, inst2_mod)
+       do an initial run test with NINST 2 (other than ocn), with mod to instance 2 (suffix: inst1_base, inst2_mod)
+       compare inst1_base with inst2_base 
+       compare inst1_mod  with inst2_mod  
+
+
+======================================================================
+    Performance Tests
+======================================================================
+
+PFS    system performance test.  Do 20 day run, no restarts
+ICP    cice performance test 
+
+======================================================================
+    SPINUP tests
+======================================================================
+
+SSP    smoke CLM spinup test (only valid for CLM compsets with CLM45 and CN or BGC)  (TODO - change to SPL)
+       do an initial spin test (setting CLM_BLDNML_OTPS to -bgc_spinup_on)
+         write restarts at the end of the run
+         short term archiving is on
+       do a hybrid non-spinup run run from the restart files generated in the first phase
+