clang-format: [JS] Fix regression caused by r239592.

Without it, it would do:

  interface I {
    x: string;
  } var y;

llvm-svn: 239593
diff --git a/clang/unittests/Format/FormatTestJS.cpp b/clang/unittests/Format/FormatTestJS.cpp
index e01637b..0f9f382 100644
--- a/clang/unittests/Format/FormatTestJS.cpp
+++ b/clang/unittests/Format/FormatTestJS.cpp
@@ -665,7 +665,8 @@
 TEST_F(FormatTestJS, InterfaceDeclarations) {
   verifyFormat("interface I {\n"
                "  x: string;\n"
-               "}");
+               "}\n"
+               "var y;");
 }
 
 TEST_F(FormatTestJS, MetadataAnnotations) {