[macosx] CARemoteLayer code refactoring and unit test

src/macosx/native/sun/awt/AWTView.m contains some code that is not compiled by default (protected with #ifdef REMOTELAYER) and included to the workspace for testing purposes only. It allows developers to test CALayer support in AWT/Java2D without need to build or download Java Plugin (which is not public, btw).

Instead, this code should be in the unit test. The test should be a standalone application, which is a very simplified version of out-of-proc plugin. It should create an instance of CEmbeddedFrame, get its CALayer pointer, wrap as a remote layer and pass to another process. That process will get this layer and attach it to a standalone top-level window (either native or even Java), similar to what server side part of Java Plugin does.

All the code in currently protected with #ifdef REMOTELAYER will thus be a part of the test, not a part of JDK.