Unioned array shapes are no longer disjunctive

[mvorisek]

Bug report

as requested phpstan/phpstan-src#5227 (comment)

Code snippet that reproduces the problem

https://phpstan.org/r/63091c63-db6c-4612-8347-a733fb79fc00

Expected output

no error on line 25 - at least before phpstan/phpstan-src#5227 (comment) the l25 was right

[phpstan-bot]

Closed via merging phpstan/phpstan-src#5229