JavaPlugin.getDefault() returning null

This is a partial rollback of commit
https://git.eclipse.org/c/platform/eclipse.platform.swt.git/commit/?id=54d81788a6efe1f9452ee795daa34c2b8d879b0a

Change-Id: I825f30f365327958ede709c1f17709fd253030e8
Signed-off-by: Sergey Prigogin <eclipse.sprigogin@gmail.com>