[EP Perf] Fix on EP Perf

[yf711]

Description

• Partially revert previous change, and
  • Redo concurrency_test_result parser outside of post.py
• Add support of syncing memtest result to db

Motivation and Context

To fix the error when CI is running on two model groups.

• When running on two model groups, the previous change wrongly navigates two levels up in the directory after running one model group, while one level is needed. After that, the script can't find another model group.
• Running on one model group can't repro the issue