[llvm] [lit] introduce --show-attempts-count (PR #142413)

[Konrad Kleine via llvm-commits]

kwk wrote:

> @kwk My expectation would be that this is only shown for tests that allow multiple attempts, and where more than one attempt is made. (Like you show in the PR description -- just without the need to also enable an extra option.)

Let me sum it up:

* Dump the option and make it the default behaviour
* Show number of attempts for all tests that were allowed multiple tries AND used more than one
* Fix the format to:

```
PASS: your-test-suite :: your-first-test.py (1 of 3)
FLAKYPASS: your-test-suite :: your-second-test.py (2 of 3) [3 of 4 attempts]
PASS: your-test-suite :: your-third-test.py (3 of 3)
```

Where

* `your-first-test.py` was only allowed one attempts,
* `your-second-test.py` was only allowed 4 attempts and used 3,
* `your-third-test.py` was only allowed i.e. 10 attempts but succeeded on first attempt (-> no output)

Correct?


https://github.com/llvm/llvm-project/pull/142413