FILE_SEG filename option - NIXLBench Support

[aranadive]

@lluki please add support for this option in the PR in the CI tests - .gitlab/test_cpp.sh.
Also add nixlbench support for this one. We will need QA to test the path option correctly. Its a new feature for FILE_SEG API - separate PR is fine.

Originally posted by @aranadive in #1635 (comment)

[lluki]

Functional testing is already included in the original PR, lets make this issue and follow up PR solely on the nixlbench modifications

[alokprasad]

@lluki @aranadive how can i use this commit , does it add FILE_SEG option to nixlbench besided VRAM/DRAM?
#1707 (comment)

[lluki]

Hi @alokprasad

I might not fully understand your question, but from other comments I have gathered you're interested in GDS.

This issue and PR #1734 that fixes it is about the "path-mode" that was recently merged #1635 . #1635 supports GDS, but nixlbench does not as run any tests on GDS. Hence, #1734 does not add GDS nixlbench support either (it just duplicates the POSIX backend evaluation).

The invocation of #1734 should be clear from the CI script update. Let me know if you have questions about that.

Can you give us some context what you are interested in?