CTest: fix comment documenting cmBoundsCheckerParser class

This was obviously copied from Source/cmGlobalXCodeGenerator.cxx during
implementation but the comment was forgotten.
Tests: add a test with custom options passed to valgrind
Merge topic 'MemChecker-improvements' into next

cc5816b Tests: add a test with custom options passed to valgrind
0dd0c3c CTest: fix comment documenting cmBoundsCheckerParser class