feat(interop-tests): build test binary inside container (backport #3441)

[mergify]

This is an automatic backport of pull request #3441 done by Mergify.
Cherry-pick of eeca244 has failed:

On branch mergify/bp/rust-v050-testplan/pr-3441
Your branch is up to date with 'origin/rust-v050-testplan'.

You are currently cherry-picking commit eeca244c.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   .github/workflows/interop-test.yml
	modified:   interop-tests/Dockerfile
	modified:   interop-tests/README.md
	modified:   interop-tests/src/bin/ping.rs

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   .dockerignore

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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