Add libc direct test for shims and update CONTRIBUTING.md

[tiif]

Add more libc direct test for shims as mentioned in #3179.

Changes:

• Added libc direct tests for rename and ftruncate64
• Added the command for running pass-dep test in CONTRIBUTING.md

[tiif]

May I know how to generate the error presented in CI locally? I tested with the command below and no error is shown.

./miri run --dep ./tests/pass-dep/shims/libc-fs.rs -Zmiri-disable-isolation --target x86_64-apple-darwin
./miri run --dep ./tests/pass-dep/shims/libc-fs.rs -Zmiri-disable-isolation --target x86_64-unknown-linux-gnu

[RalfJung]

May I know how to generate the error presented in CI locally?

You have to check which target the tests are failing for. If you scroll up from the test failure you will see

## Running ui tests in tests/pass-dep against miri for i686-unknown-linux-gnu

So the target is i686-unknown-linux-gnu.

[tiif]

@RalfJung
Ok, the CI is finally green. Please take a look whenever you find it convenient, thanks!

[RalfJung]

LGTM, thanks!
Please squash the commits.

[tiif]

Sorry for doing force push, this is my first time using squash, so I am not sure why the push is rejected after squashing. Thank you for your guidance and multiple rounds of reviews for this PR, I really learned a lot! I will work on implementing some easier shim next.

[RalfJung]

Force-pushing is expected after squashing. :) This looks right, thanks for the PR!
@bors r+

[bors]

📌 Commit 77a898b has been approved by RalfJung

It is now in the queue for this repository.

[bors]

⌛ Testing commit 77a898b with merge c8649a5...

[bors]

☀️ Test successful - checks-actions
Approved by: RalfJung
Pushing c8649a5 to master...