[iOS] Since js_core is located under Library, update the js path.
CB-5671 Don't fail plugin loading if plugin modules are already loaded.

This can happen when a build step concats all your JS.
CB-5671 setTimeout to allow concat'ed JS to load before pluginLoader.load()
Merge remote-tracking branch 'cordova/master'
[Doing-315]Fixed failed auto tests.
Fixed failed browser tests