Added stub files and tests for array_* functions.

[mad-briller]

closes phpstan/phpstan#7707

functions stubbed:

array_diff_uassoc
array_diff_ukey
array_intersect_uassoc
array_intersect_ukey
array_udiff_assoc
array_udiff_uassoc
array_uintersect_assoc
array_uintersect_uassoc
array_uintersect

whilst adding these, phpstan warned because i didn't add array iterable types for the returns so i've specified them in the stubs, however i noticed this return type extension plugin which seems to be overriding them anyway, if theres something i should do instead let me know

[ondrejmirtes]

The TK templates should have array-key bounds instead of mixed.

[mad-briller]

i tried that but it seemed to break the templating by using array-key or even int|string and i couldn't quite figure out why

when using array-key it reverted to showing errors like this:

+30: Parameter #3 $data_comp_func of function array_diff_uassoc expects callable(mixed, mixed): int, Closure(string, string): int<-1, 1> given.

[ondrejmirtes]

Please push the stubs with array-key and then try to figure out why these errors are reported by debugging the codebase :) Thanks.

[ondrejmirtes]

Feel free to open a new PR if you decide to finish it, thank you :)