Cherry-pick more 7.11 changes to 8.3

Cherry-picked commits:
    b711aa82: Add Unix domain socket support to gdbserver 7.9.1.

The upstream domain socket change actually get reverted.
Original upstream change: f19c7ff839d7a32ebb48482ae7d318fb46ca823d
Reverted in: 80e24d09860dbeba7d435b4a4f0990f85dbc084e

Test: build
Bug: 62547070
Change-Id: I574cc11792fac018453e05d82fd835c4d45de7c1