CE: Introduce CompositionEngine::dump()

Allow any CompositionEngine state to be dumped as part of
SurfaceFlinger's dump.

Test: atest libsurfaceflinger_unittest libcompositionengine_test
Test: go/wm-smoke
Bug: 121291683
Change-Id: I4b87ff912c767538f2d371c342f782e92c4e74e9
5 files changed