Treat array-shapes without keys as tuples

[zonuexe]

refs phpstan/phpstan#12725

[zonuexe]

I'm a bit surprised that this single change digs up list-shapes that were previously imported from Psalm.

2) PHPStan\Analyser\NodeScopeResolverTest::testFile with data set "tests/PHPStan/Analyser/nsrt/list-shapes.php" ('/home/runner/work/phpstan-src...es.php')
Failed assertions in /home/runner/work/phpstan-src/phpstan-src/tests/PHPStan/Analyser/nsrt/list-shapes.php:

Line 21:
Expected: array{'a'}
Actual:   list{'a'}

Line 22:
Expected: array{'a', 'b'}
Actual:   list{'a', 'b'}

Line 23:
Expected: array{0: 'a', 1?: 'b'}
Actual:   list{0: 'a', 1?: 'b'}

[ondrejmirtes]

We tried something similar here but decided against it #3381

[ondrejmirtes]

I don't think we should make any difference between array{int} and array{0: int}`. It should be the same thing...