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

test/codegen/expect/collection/iterable_zip.js

 dart_library.library('collection/iterable_zip', null, /* Imports */[
   "dart/_runtime",
   'dart/collection',
   'dart/core'
 ], /* Lazy imports */[
 ], function(exports, dart, collection, core) {
   'use strict';
   let dartx = dart.dartx;
   const _iterables = Symbol('_iterables');
   class IterableZip extends collection.IterableBase$(core.List) {
@@ skipping 11 matching lines @@
   });
   dart.defineExtensionMembers(IterableZip, ['iterator']);
   const _iterators = Symbol('_iterators');
   const _current = Symbol('_current');
   class _IteratorZip extends core.Object {
     _IteratorZip(iterators) {
       this[_iterators] = dart.as(iterators, core.List$(core.Iterator));
       this[_current] = null;
     }
     moveNext() {
-      if (dart.notNull(this[_iterators][dartx.isEmpty]))
-        return false;
+      if (dart.notNull(this[_iterators][dartx.isEmpty])) return false;
       for (let i = 0; dart.notNull(i) < dart.notNull(this[_iterators][dartx.length]); i = dart.notNull(i) + 1) {
         if (!dart.notNull(this[_iterators][dartx.get](i).moveNext())) {
           this[_current] = null;
           return false;
         }
       }
       this[_current] = core.List.new(this[_iterators][dartx.length]);
       for (let i = 0; dart.notNull(i) < dart.notNull(this[_iterators][dartx.length]); i = dart.notNull(i) + 1) {
         this[_current][dartx.set](i, this[_iterators][dartx.get](i).current);
       }
       return true;
     }
     get current() {
       return this[_current];
     }
   }
   _IteratorZip[dart.implements] = () => [core.Iterator$(core.List)];
   dart.setSignature(_IteratorZip, {
     constructors: () => ({_IteratorZip: [_IteratorZip, [core.List]]}),
     methods: () => ({moveNext: [core.bool, []]})
   });
   // Exports:
   exports.IterableZip = IterableZip;
 });