Update tests to use %clang instead of 'clang', and forcibly disable use of '
clang ' or ' clang -cc1 ' or ' clang-cc ' in test lines (by substituting them to
garbage).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@91460 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Driver/preprocessor.c b/test/Driver/preprocessor.c
index 51b6fc5..09c1f6c 100644
--- a/test/Driver/preprocessor.c
+++ b/test/Driver/preprocessor.c
@@ -1,4 +1,4 @@
-// RUN: clang -E -x c-header %s > %t
+// RUN: %clang -E -x c-header %s > %t
 // RUN: grep 'B B' %t
 
 #define A B