Short IPC tests

[Yaxuan-w]

Description

Changed to use shorter IPC tests and replaced the older ipc_performance/total_runtime with newer one. Changed to use relative path in test files and scripts. Updated README

Type of change

• [ ] New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Checklist:

• [ ] My code follows the style guidelines of this project
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] Any dependent changes have been added to a pull request and/or merged in other modules (native-client, lind-glibc, safeposix-rust)