SF: Fix leak in unit tests

Remove the sp<SurfaceFlinger> cycle in WindowInfosListenerInvoker, such
that TestableSurfaceFlinger can delete its SurfaceFlinger instance.

Also, remove the indirection for the windowInfosReported callback.

Bug: 213688734
Test: No spam/aborts regarding leaks.
Change-Id: I50450881e8a37ff64dab12bf6afe02711cdd93b7
3 files changed