Define command line args in soong_build .

They used to be defined in Blueprint but since it doesn't have a
separate existence anymore, we can consolidate all command line
arguments here.

Note that Blueprint is called directly from soong_ui, but that happens
by a simple Go function call and not by invoking a separate binary, so
command line arguments are not needed there.

Test: Presubmits.
Change-Id: Ifa2c101ddbe424b76fc5a508d3d41c329e7353ca