This works by setting the SOONG_UI_DELVE= environment variable to the
port on which soong_ui should accept a Delve connection on.
This is achieved by reusing the Delve execution logic between soong_ui
and soong_build.
Test: Manual.
Change-Id: Id2c1d4b6faac1a4a3918c91030ce2239f7daf54f
This lets one avoid any decisions as to when to chdir there during its
execution and leads to better sandboxing because the pwd doesn't leak to
init() functions anymore.
Test: Manual.
Change-Id: I1560da8ed3a621249426f9e8908aa890c21e13ba