Surface: Add force disconnection method.

Add a new method forceScopedDisconnect to Surface. This will
be used by the framework to force disconnection at times where
the underlying GraphicBufferProducer may be about to be reused.
This is scoped by PID to avoid conflicting with remote producers.

Bug: 30236166
Change-Id: I857216483c0b550f240b3baea41977cbc58a67ed