drm_hwcomposer: CI: Increase coverage

Add the following files to the build:
backend/BackendClient.cpp
backend/Backend.cpp
backend/BackendManager.cpp
backend/BackendRCarDu.cpp
bufferinfo/legacy/BufferInfoImagination.cpp
bufferinfo/legacy/BufferInfoLibdrm.cpp
bufferinfo/legacy/BufferInfoMaliHisi.cpp
bufferinfo/legacy/BufferInfoMaliMediatek.cpp
bufferinfo/legacy/BufferInfoMaliMeson.cpp
bufferinfo/legacy/BufferInfoMinigbm.cpp
compositor/DrmDisplayComposition.cpp
compositor/DrmDisplayCompositor.cpp
compositor/Planner.cpp
drm/DrmGenericImporter.cpp
DrmHwcTwo.cpp
drm/ResourceManager.cpp
drm/VSyncWorker.cpp
tests/worker_test.cpp
utils/autolock.cpp

Files 'bufferinfo/BufferInfoMapperMetadata.cpp' and 'utils/hwcutils.cpp' require
a lot of additional stubs, therefore move them out of the scope of this commit.

In order to build in linux environment some Android stubs are required.
Put them into .ci/android_stubs

'utils/gralloc.h' isn't planned to use in pure-linux builds, therefore remove
it from 'utils' and put it into '.ci/android_stubs/hardware/'

Fix minor tidy fails.

Fix linux build fails (missing includes) due to differences between libc and
bionic.

Comment-out some sections in 'tests/test_include' which aren't used by drm_hwc
but causing build failures for CI due to missing dependencies.