clang-format: [JS] Support different function literal style.

Before:
  goog.array.forEach(array, function() {
                              doSomething();
                              doSomething();
                            },
                     this);

After:
  goog.array.forEach(array, function() {
    doSomething();
    doSomething();
  }, this);

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@209291 91177308-0d34-0410-b5e6-96231b3b80d8