cosmetic: auc_3g_test: improve test debugging tools

In the test failure mismatch printf, better indicate the place of first
mismatch. Helpful if some byte within a hexdump differs, the case when
debugging AUTS.

Copy some optarg code from openbsc's msc_vlr tests to provide verbose mode that
prints log statements' source file and line.

Change-Id: I1b23da055b5edacba09310411caf43c4cd1c29bc
1 file changed