SurfaceFlinger: Add exclusion list for captureLayers.

Among other use cases, WM needs to be able to omit the IME from Task Snapshots,
even while it is on-screen.

Bug: 126614127
Test: Transaction_test.cpp#CaptureLayerExclude,CaptureLayerExcludeTree
Change-Id: I055d99106c9ce2ed90d64eca06961d88cbd5e2d4
8 files changed