Convert Preprocessor Clang tests to FileCheck in regards to PR5307.

llvm-svn: 85199
diff --git a/clang/test/Preprocessor/comment_save.c b/clang/test/Preprocessor/comment_save.c
index 30b0434..ae609b11 100644
--- a/clang/test/Preprocessor/comment_save.c
+++ b/clang/test/Preprocessor/comment_save.c
@@ -1,7 +1,8 @@
-// RUN: clang-cc -E -C %s | grep '^// foo$' &&
-// RUN: clang-cc -E -C %s | grep -F '^/* bar */$'
+// RUN: clang-cc -E -C %s | FileCheck -strict-whitespace %s
 
 // foo
-/* bar */
+// CHECK: // foo
 
+/* bar */
+// CHECK: /* bar */