[Do Not Merge] Testing CI: Verify commits in beta are in stable.

[yaymukund]

Note: This is not to be merged or reviewed.

This PR exists to test the CI check I've written to address #74721

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @Mark-Simulacrum (or someone else) soon.

Please see the contribution instructions for more information.

[rust-highfive]

⚠️ Warning ⚠️

• Pull requests are usually filed against the master branch for this repo, but this one is against beta. Please double check that you specified the right target!

[rust-log-analyzer]

A job failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

Resolving deltas: 100% (1216323/1216323)
Resolving deltas: 100% (1216323/1216323), completed with 9611 local objects.
From https://github.com/rust-lang/rust
 * [new branch]              beta                   -> origin/beta
 * [new branch]              cranelift-rebase       -> origin/cranelift-rebase
 * [new branch]              issue-85533            -> origin/issue-85533
 * [new branch]              master                 -> origin/master
 * [new branch]              nellshamrell/fix-80658 -> origin/nellshamrell/fix-80658
 * [new branch]              revert-82057-cstr      -> origin/revert-82057-cstr
 * [new branch]              stable                 -> origin/stable
 * [new branch]              yeet-unused-substs     -> origin/yeet-unused-substs
✓ `3998e9860c73ae7a0dfdf9cf7f95483cd144d191` backports nothing
✓ `f36eb4df2091d5c684bb596cbef188716b5c17d6` backports `4a3e73643ab`
✓ `580dd2e27200bd8880a5f74e2949ec7170d62b9e` backports `fffa88eb27b451508a9f1abacf7ecbe9de9302f3`


All commits in \`HEAD\` are required to have a corresponding upstream commit.
It looks like the following commits:
    9a81cef29a40e654d1a5c94875a535a191993f48
    eda66493bff8a9b038f8935e4f060386c60738e3
    86cefca0e9d83b34c5bc986038d7667b9e6b257e
    739431df9531d3029806906157ac860d689dedee
    739431df9531d3029806906157ac860d689dedee
    f2ccd2a07e3f293671f3e9e64afeddcddd8d2d76

do not match any commits in `beta`. If this was intended, add the text
\`backport-of: <SHA of a commit already in master>\`
somewhere in the message of each of these commits.
Error: Found incorrectly marked commits.

The following commits:


    4d7aa5c940fc9934417debdbb599864e887d054c

have commit messages marked \`backport-of: <SHA>\`, but the SHA is not in
\`master\`.

✓ `3998e9860c73ae7a0dfdf9cf7f95483cd144d191` backports nothing
✓ `f36eb4df2091d5c684bb596cbef188716b5c17d6` backports `4a3e73643ab`


All commits in \`HEAD\` are required to have a corresponding upstream commit.
It looks like the following commits:
    9a81cef29a40e654d1a5c94875a535a191993f48
    eda66493bff8a9b038f8935e4f060386c60738e3
    86cefca0e9d83b34c5bc986038d7667b9e6b257e
    739431df9531d3029806906157ac860d689dedee
    739431df9531d3029806906157ac860d689dedee
    f2ccd2a07e3f293671f3e9e64afeddcddd8d2d76

do not match any commits in `master`. If this was intended, add the text
\`backport-of: <SHA of a commit already in master>\`
somewhere in the message of each of these commits.
Error: Found incorrectly marked commits.

The following commits:


    4d7aa5c940fc9934417debdbb599864e887d054c

have commit messages marked \`backport-of: <SHA>\`, but the SHA is not in
\`master\`.
##[error]Process completed with exit code 1.
Post job cleanup.

[yaymukund]

#87604 shall soon merge ☺️