Rephrase this test to help debug a buildbot issue

llvm-svn: 258526
diff --git a/clang/test/Modules/ExtDebugInfo.cpp b/clang/test/Modules/ExtDebugInfo.cpp
index dfc8be5..3b4547a8 100644
--- a/clang/test/Modules/ExtDebugInfo.cpp
+++ b/clang/test/Modules/ExtDebugInfo.cpp
@@ -109,4 +109,5 @@
 // CHECK: !DICompileUnit(
 // CHECK-SAME:           splitDebugFilename:
 // CHECK-SAME:           dwoId:
-// CHECK-PCH:            dwoId: 18446744073709551614
+// CHECK-PCH: !DICompileUnit({{.*}}splitDebugFilename:
+// CHECK-PCH:                dwoId: 18446744073709551614