memory/function/memeq: fix mem size list setup

Fixes: https://issues.redhat.com/browse/RHELTEST-719
Resolve: https://issues.redhat.com/browse/RHELTEST-719
The reason why the flag dir disappered after reboot is the OUTPUTFILE
variable is a tmp dir with mktemp:
Setting OUTPUTFILE as /tmp/tmp.NmJ62TvG1o/resultoutputfile.log

This issue causes several issues:
1) kernel panic on memory deadlock on kernel-debug x86_64, where only 1.4G
   total memory left for testing and can't boot.

2) causes 6T machine kernel panic in VMM-FUNCTION test, as there's the
   no flag dir exist, so the test finally existed with mem=4G in command
   line without cleanup:
   """
   Sorry, the system RAM is too low to test.
   """

So we choose to use a fixed dirname as the flag dir name.