cmd/coordinator: add CONNECT proxy support in reverse buildlet mode

Updates golang/go#15072

Change-Id: I56767a421428418add66aa9b50f0baf9aa202538
Reviewed-on: https://go-review.googlesource.com/46724
Reviewed-by: Andrew Bonventre <andybons@google.com>
Reviewed-by: Shawn Walker-Salas <shawn.walker@oracle.com>
1 file changed