Do not report failure line numbers if file not setup

Do not report failure line numbers if file not setup

When running the master suite failure line numbers are written to
a file. Usually this is fine. However, the check_mem_leak.c test
re-uses the same tests. As a result, every time a failure is hit
a SEGV occurs because the file is never setup.

The memory leak test does not check against the line numbers,
so omitting these are fine. This fix prevents lots of SEGV
failures when running check_mem_leak.c under valgrind.