Add ability to run clang tests under valgrind. Patch by Sam Bishop.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@48621 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Makefile b/test/Makefile
index 8c8fe51..ec4d45e 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -9,7 +9,7 @@
 endif
 
 all::
-	PATH=$$PATH:$(ToolDir):$(LLVM_SRC_ROOT)/test/Scripts \
+	PATH=$$PATH:$(ToolDir):$(LLVM_SRC_ROOT)/test/Scripts VG=$(VG) \
           find $(TESTDIRS) \( -name '*.c' -or -name '*.cpp' -or -name '*.m' \) \
 	      -print -exec ./TestRunner.sh {} \;