Fix the test added in r260266

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@260276 91177308-0d34-0410-b5e6-96231b3b80d8

test/Frontend/plugins.c

 // RUN: %clang_cc1 -load %llvmshlibdir/PrintFunctionNames%pluginext -plugin print-fns %s 2>&1 | FileCheck %s
-// RUN: %clang_cl -Xclang -load -Xclang %llvmshlibdir/PrintFunctionNames%pluginext -Xclang -plugin -Xclang print-fns %s 2>&1 | FileCheck %s
+// RUN: %clang_cl -c -Xclang -load -Xclang %llvmshlibdir/PrintFunctionNames%pluginext -Xclang -plugin -Xclang print-fns -Tc %s 2>&1 | FileCheck %s
 // REQUIRES: plugins, examples
 
 // CHECK: top-level-decl: "x"