Revert "Bazel: Fix toolchain vanilla to not hard code java 8"

This reverts commit aee1f80.

Reason for revert: The upstream issue: [1] was fixed in 1.0
Bazel release and gerrit switched to using Bazel 1.1 recently.

[1] bazelbuild/bazel#9415

Change-Id: I6f81b187e0265ff797589479b7bff98a487c561a

Documentation/dev-bazel.txt

@@ -44,8 +44,8 @@ provide the path to JDK home:
     --define=ABSOLUTE_JAVABASE=<path-to-java-12> \
     --javabase=@bazel_tools//tools/jdk:absolute_javabase \
     --host_javabase=@bazel_tools//tools/jdk:absolute_javabase \
-    --host_java_toolchain=//tools:toolchain_vanilla \
-    --java_toolchain=//tools:toolchain_vanilla \
+    --host_java_toolchain=@bazel_tools//tools/jdk:toolchain_vanilla \
+    --java_toolchain=@bazel_tools//tools/jdk:toolchain_vanilla \
     :release
 ```
 
@@ -57,8 +57,8 @@ bazel test runs the test using the target javabase:
     --define=ABSOLUTE_JAVABASE=<path-to-java-12> \
     --javabase=@bazel_tools//tools/jdk:absolute_javabase \
     --host_javabase=@bazel_tools//tools/jdk:absolute_javabase \
-    --host_java_toolchain=//tools:toolchain_vanilla \
-    --java_toolchain=//tools:toolchain_vanilla \
+    --host_java_toolchain=@bazel_tools//tools/jdk:toolchain_vanilla \
+    --java_toolchain=@bazel_tools//tools/jdk:toolchain_vanilla \
     //...
 ```
 
@@ -70,8 +70,8 @@ $ cat << EOF > ~/.bazelrc
 > build --define=ABSOLUTE_JAVABASE=<path-to-java-12>
 > build --javabase=@bazel_tools//tools/jdk:absolute_javabase
 > build --host_javabase=@bazel_tools//tools/jdk:absolute_javabase
-> build --host_java_toolchain=//tools:toolchain_vanilla
-> build --java_toolchain=//tools:toolchain_vanilla
+> build --host_java_toolchain=@bazel_tools//tools/jdk:toolchain_vanilla
+> build --java_toolchain=@bazel_tools//tools/jdk:toolchain_vanilla
 > EOF
 ```
 

tools/BUILD

@@ -15,19 +15,6 @@ py_binary(
     visibility = ["//visibility:public"],
 )
 
-# TODO(davido): Remove this workaround and switch to using toolchain_vanilla
-# from this Bazel package again: @bazel_tools//tools/jdk:toolchain_vanilla,
-# when this issue is fixed: https://github.com/bazelbuild/bazel/issues/9415.
-default_java_toolchain(
-    name = "toolchain_vanilla",
-    forcibly_disable_header_compilation = True,
-    javabuilder = ["@bazel_tools//tools/jdk:vanillajavabuilder"],
-    jvm_opts = [],
-    source_version = "",
-    target_version = "",
-    visibility = ["//visibility:public"],
-)
-
 default_java_toolchain(
     name = "error_prone_warnings_toolchain",
     bootclasspath = ["@bazel_tools//tools/jdk:platformclasspath.jar"],