[BugFest] Feature request #38685: str_[i]replace(): Add support for (string needle, array replace)

Hi, I just created a PR for a feature request lying around since 2006 : https://github.com/php/php-src/pull/980 It adds support in str_replace() and str_ireplace() for the combination of (string needle, array replace). In this case, each occurrence of the needle is replaced with an element f the 'replace' array, looping if count(replace) is lower than count(needles) in subject. It is interesting for cyclic replacements (alternating line colors, for instance). The PR includes the needed tests. As the BC break is minimal, do you think it can be merged to the PHP7 branch or do I need to write an RFC ? Regards, François