[PATCH] allow array_reduce to have a mixed starting value

I opened bug #33447 the other day which is a feature request to allow array_reduce to have a mixed starting value. It currently will only accept integers which I feel is an odd limitation since the array can hold any value. This is a trivial patch to array_reduce which removes this limitation. All the tests passed with this modification (that passed without it). I also included a test file which tests the new functionality and provides a few examples of what it could be useful for. David