clang-format: [JS] Understand named function literals.

Before:
  return {a: function SomeFunction(){// ...
                                     return 1;
  }
  }
  ;

After:
  return {
    a: function SomeFunction() {
      // ...
      return 1;
    }
  };

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@210887 91177308-0d34-0410-b5e6-96231b3b80d8