ATest: Host native test config auto-gen support.

Autogenerate HostGTest test config for better user
experience of hostside native tests.

BUG: 80298359

Test: . build/envsetup.sh ; lunch aosp_x86_64-eng ; make -j
      . build/envsetup.sh ; lunch aosp_x86_64-eng ; make -j hello_world_test
      . build/envsetup.sh ; lunch aosp_x86_64-eng ; make -j CtsLiblogTestCases_list

Change-Id: Iee1db17f8957d3c1cd80c9aae1996a72b48413d9