Make VectorAgg support different child plans

Vectorized aggregation assumes that it runs on top of a
DecompressChunk child node, which makes it difficult to support other
child plans; including those that fetch data via Hypercore TAM.

Most of the DecompressChunk-specific code for planning VectorAgg
relates to identifying vectorizable columns. This code is moved to a
separate source file so that the main planning code is mostly
child-node independent.

tsl/src/nodes/decompress_chunk/vector_quals.h

@@ -24,11 +24,13 @@ typedef struct VectorQualInfo
 	 */
 	Index rti;
 
+	bool reverse;
 	/*
-	 * Array indexed by uncompressed attno indicating whether an
-	 * attribute/column is a vectorizable type.
+	 * Arrays indexed by uncompressed attno indicating whether an
+	 * attribute/column is a vectorizable type and/or a segmentby attribute.
 	 */
 	bool *vector_attrs;
+	bool *segmentby_attrs;
 } VectorQualInfo;
 
 /*

tsl/src/nodes/vector_agg/CMakeLists.txt

@@ -4,5 +4,6 @@ set(SOURCES
     ${CMAKE_CURRENT_SOURCE_DIR}/exec.c
     ${CMAKE_CURRENT_SOURCE_DIR}/grouping_policy_batch.c
     ${CMAKE_CURRENT_SOURCE_DIR}/grouping_policy_hash.c
-    ${CMAKE_CURRENT_SOURCE_DIR}/plan.c)
+    ${CMAKE_CURRENT_SOURCE_DIR}/plan.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/plan_decompress_chunk.c)
 target_sources(${TSL_LIBRARY_NAME} PRIVATE ${SOURCES})