clang-format: [JS] Fix bug in type colon detection.

Before, this couldn't be formatted at all:
  class X {
    subs = {
      'b': {
        'c': 1,
      },
    };
  }

llvm-svn: 238907
diff --git a/clang/unittests/Format/FormatTestJS.cpp b/clang/unittests/Format/FormatTestJS.cpp
index 80a3e0a..3ed3cde 100644
--- a/clang/unittests/Format/FormatTestJS.cpp
+++ b/clang/unittests/Format/FormatTestJS.cpp
@@ -631,6 +631,15 @@
   verifyFormat("class C {\n  static x(): string { return 'asd'; }\n}");
   verifyFormat("class C extends P implements I {}");
   verifyFormat("class C extends p.P implements i.I {}");
+
+  // ':' is not a type declaration here.
+  verifyFormat("class X {\n"
+               "  subs = {\n"
+               "    'b': {\n"
+               "      'c': 1,\n"
+               "    },\n"
+               "  };\n"
+               "}");
 }
 
 TEST_F(FormatTestJS, InterfaceDeclarations) {