[5.8] Add replace() and replaceRecursive() methods on collections

[iamgergo]

This PR implements the PHP array_replace and the array_replace_recursive behavior on the collections.

With associative array keys, array_merge and array_replace behave the same way. However, with numeric keys/indexes, the merge appends the values to the array, but replace overrides the original value of the specific indexes.

[ahinkle]

Resubmit of #20220.

[iamgergo]

Yes, the functionality is the same, but this PR contains more tests for both functions.

Also, there is a suggestion to use map instead of replace. Well, it can be a good alternative for simple replacements, but for nested and recursive replacements it can be quite tricky.

The other problem with map is that, if the replacement array contains keys, that the original collection does not, we don't really have access to those items. The replace would append the new keys/values to the original collection.

Maybe using map and diff could solve this, but again, if it's a nested replacement, this issue is not solvable simply.