Fix Android mode support  on MacOS X

The change in 2.2 to using the Oracle appbundler means that javac is no
longer available, and copying it in from outside leads to the Android
SDK utilities breaking (pre-dexing hangs, or javac hangs, or it builds
a broken Android apk that doesn't run.)

This change adds back in the javac from the JDK that Android mode needs,
and avoids breaking the Android SDK utilities in the process.

The changes to the Toolkit.setIcon() method also broke a bunch of modes, in
particular the Permissions dialog in which one could select permissions for the
AndroidManifest.  This change stubs out the setIcon(Frame f) method, letting 
them run again.