Ease debugging BaselineNeonErrorFormatterIntegrationTest

[staabm]

I see this test fail more often on PRs lately with output like:

php vendor/bin/paratest --runner WrapperRunner --no-coverage --group exec
ParaTest v6.6.3 upon PHPUnit 9.6.20 by Sebastian Bergmann and contributors.

............................E...                                 32 / 32 (100%)

Time: 00:35.534, Memory: 80.00 MB

There was 1 error:

1) PHPStan\Command\ErrorFormatter\BaselineNeonErrorFormatterIntegrationTest::testRunUnixFileWithWindowsBaseline
PHPStan\ShouldNotHappenException: Could not clear result cache.

D:\a\phpstan-src\phpstan-src\tests\PHPStan\Command\ErrorFormatter\BaselineNeonErrorFormatterIntegrationTest.php:74
D:\a\phpstan-src\phpstan-src\tests\PHPStan\Command\ErrorFormatter\BaselineNeonErrorFormatterIntegrationTest.php:54

FAILURES!
Tests: 32, Assertions: 82, Errors: 1.
make: *** [Makefile:9: tests-integration] Error 2

lets see whether we can get a more meaningful output which might help to fix the underlying problem

[phpstan-bot]

This pull request has been marked as ready for review.

[ondrejmirtes]

I don't think we need the debugging. It's obvious what's going on. paratest runs in multiple threads. All these test methods share the same result cache file. Windows doesn't like multiple processes accessing the same file and sometimes fails.

The solution is to have different tmpDir for each of these tests.