Fix crash where trim memory resulted in HWUI deleting the surface.

When HWUI is given the TRIM_MEMORY_COMPLETE signal it deletes all
of the associated GPU resources. In doing so it also deleted the
GL/Vk handle to the the ANativeWindow. So if the app attempted to
recover and draw new content it would crash because we no longer
had a surface to reinitialize and render into.

Test: atest hwui_unit_tests
Bug: 233388563
Change-Id: I54f3f0dadc3dfc89d2b1f567d36611f6a966c4f0