Move `src/test/run-fail` tests to UI

[JohnTitor]

TL;DR

Move src/test/run-fail tests to UI to unify the test structure.

Links and Details

• submitted PR: Move tests from test/run-fail to UI rust#71185
• original issue: Cleanup: Move src/test/run-fail to src/test/ui rust#65440
• unresolved issue: Cleanup: Migrate run-fail tests in src/test/ui from error-pattern to check-run-results rust#65865
• previous attmpt: Move tests from src/test/run-fail/ to src/test/ui/ rust#65506

Questions

• Does this remove all uses of run-fail?
• How will Cleanup: Migrate run-fail tests in src/test/ui from error-pattern to check-run-results rust#65865 get resolved?
• Any other lingering bits of work?

Mentors or Reviewers

@nikomatsakis

[petrochenkov]

I support the change, multiple other test suites were already successfully migrated to UI, including run-pass.

If some tests cannot be migrated right now due to heavily platform-dependent output or similar reasons, they can stay in run-fail for now and be dealt with later.

It's more convenient to fix rust-lang/rust#65865 after the run-fail -> ui change, but soon enough to avoid new uses of error-pattern for runtime output.

[Mark-Simulacrum]

(I suspect @petrochenkov may have forgotten to, but regardless I'm willing to do it: @rustbot seconded).

[Mark-Simulacrum]

Gah, bad bot, @rustbot seconded.

[petrochenkov]

I didn't even know the automation was already implemented.
Is it documented anywhere? EDIT: https://github.com/rust-lang/triagebot/wiki/Major-changes

[spastorino]

Added to our compiler team meeting agenda, removing to-announce label.

[nikomatsakis]

Huzzah! This proposal has been accepted.