tests: Use %clangxx when using driver for C++, in case C++ support is disabled.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@107153 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Misc/macro-backtrace-limit.c b/test/Misc/macro-backtrace-limit.c
index bc7a4da..1e512fe 100644
--- a/test/Misc/macro-backtrace-limit.c
+++ b/test/Misc/macro-backtrace-limit.c
@@ -1,4 +1,4 @@
-// RUN: %clang-cc1 -fsyntax-only -fmacro-backtrace-limit 5 %s > %t 2>&1 
+// RUN: %clang_cc1 -fsyntax-only -fmacro-backtrace-limit 5 %s > %t 2>&1 
 // RUN: FileCheck %s < %t
 
 #define M1(A, B) ((A) < (B))