Fix GraphicBuffer leaks in system_server

IWindowId is being kept alive by binder in certain cases, which
will leak WindowState, which can leak a whole lot including
the snapshot GraphicBuffer.

- Fix a leak in WindowContainer.mTmpChain1/2
- When the window gets removed, make sure to release the reference
to the window state so even if Binder keeps IWindowId alive, we
don't keep WindowState alive
- Make sure that even if we leak TaskSnapshotSurface we don't leak
the GraphicBuffer.

Test: Boot, some basic sanity testing.
Bug: 36279079
Change-Id: I4a0a784b32bc2df47934b1bed1d62b0682beb2dd