chore(ci): re-use cache key from build workflow

[flrgh]

This makes build cache key generation reusable across different workflows. The test and release workflows now use the same "recipe" for cache key generation--no more copy/paste.

[curiositycasualty]

Good idea.

[flrgh]

I've also updated perf.yml since it was also using a one-off cache key formula.

[team-gateway-bot]

The backport to release/3.4.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-release/3.4.x release/3.4.x
# Navigate to the new working tree
cd .worktrees/backport-release/3.4.x
# Create a new branch
git switch --create backport-11299-to-release/3.4.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 68b7b6f9cb9eb52af0ed558b2952a3239926b5b7
# Push it to GitHub
git push --set-upstream origin backport-11299-to-release/3.4.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-release/3.4.x

Then, create a pull request where the base branch is release/3.4.x and the compare/head branch is backport-11299-to-release/3.4.x.

[fffonion]

this should not be set for non-release workflows (build_and_test, perf), because almost every PR change lua codes and cause a cache miss (unless the PR only changes tests, which is a less common case).