gdb/testsuite: use foreach_with_prefix in gdb.guile/scm-ports.exp

Simplify things a bit using foreach_with_prefix.  The only expected
change is in the naming of tests.

Change-Id: Icb5e55207e0209e0d44d9e7c16a2f5e11aa29017
Approved-By: Andrew Burgess <aburgess@redhat.com>
1 file changed