Fix buildbot failure from r373217 (don't match metadata id exactly)

Fix this failure by ignoring the id of the metadata being checked:
    http://green.lab.llvm.org/green/job/clang-stage1-cmake-RA-incremental/3046/consoleFull#-21332887158254eaf0-7326-4999-85b0-388101f2d404

llvm-svn: 373237

clang/test/Frontend/stdin-input.c

@@ -2,6 +2,6 @@
 // RUN: -Xclang -main-file-name -Xclang test/foo.c -x c - -o - | FileCheck %s
 // CHECK: ; ModuleID = 'test/foo.c'
 // CHECK: source_filename = "test/foo.c"
-// CHECK: !1 = !DIFile(filename: "test/foo.c"
+// CHECK: !DIFile(filename: "test/foo.c"
 
 int main() {}