JS: Format if statements with no else on a single line

lib/runtime/dart/_metadata.js

 dart_library.library('dart/_metadata', null, /* Imports */[
   "dart/_runtime",
   'dart/core'
 ], /* Lazy imports */[
 ], function(exports, dart, core) {
   'use strict';
   let dartx = dart.dartx;
   class SupportedBrowser extends core.Object {
     SupportedBrowser(browserName, minimumVersion) {
-      if (minimumVersion === void 0)
-        minimumVersion = null;
+      if (minimumVersion === void 0) minimumVersion = null;
       this.browserName = browserName;
       this.minimumVersion = minimumVersion;
     }
   }
   dart.setSignature(SupportedBrowser, {
     constructors: () => ({SupportedBrowser: [SupportedBrowser, [core.String], [core.String]]})
   });
   SupportedBrowser.CHROME = "Chrome";
   SupportedBrowser.FIREFOX = "Firefox";
   SupportedBrowser.IE = "Internet Explorer";
@@ skipping 28 matching lines @@
   dart.setSignature(Unstable, {
     constructors: () => ({Unstable: [Unstable, []]})
   });
   // Exports:
   exports.SupportedBrowser = SupportedBrowser;
   exports.Experimental = Experimental;
   exports.DomName = DomName;
   exports.DocsEditable = DocsEditable;
   exports.Unstable = Unstable;
 });