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

llvm-svn: 107153
diff --git a/clang/test/Lexer/has_feature_rtti.cpp b/clang/test/Lexer/has_feature_rtti.cpp
index 690906c..4bfeead 100644
--- a/clang/test/Lexer/has_feature_rtti.cpp
+++ b/clang/test/Lexer/has_feature_rtti.cpp
@@ -1,5 +1,5 @@
-// RUN: %clang -E -frtti %s -o - | FileCheck --check-prefix=CHECK-RTTI %s
-// RUN: %clang -E -fno-rtti %s -o - | FileCheck --check-prefix=CHECK-NO-RTTI %s
+// RUN: %clang_cc1 -E %s -o - | FileCheck --check-prefix=CHECK-RTTI %s
+// RUN: %clang_cc1 -E -fno-rtti %s -o - | FileCheck --check-prefix=CHECK-NO-RTTI %s
 
 #if __has_feature(cxx_rtti)
 int foo();