Add resolv_unit_test_config.xml for mts

MTS can't find the multiarch test binary correctly.
This xml file is used to let MTS know which test binary should be took.
It is a temporary solution, hopefully we can get rid of the xml soon.

Bug: 151122604
Test: forrest
Change-Id: I45e45912f91e8d78891a8658f9f2e27c7e6252da