The range-stepping tests fail with "maint set target-non-stop on" mode
because exec_cmd_expect_vCont_count doesn't know that in non-stop
mode, vCont's reply is simply "OK".
gdb/testsuite/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* lib/range-stepping-support.exp (exec_cmd_expect_vCont_count):
Handle non-stop mode vCont replies.