Fix crash when EGLSurface is no longer valid.

The EGLSurface stored in the pipeline can become obsolete if the
EglManager/RenderThread has to destroy the context.  This CL enables the
RenderThread to notify all active pipelines that their surface is invalid.

Bug: 115290937
Test: hwui_unit_tests
Change-Id: Ib3054822273bc35406630b7442229a81b39a2c91