Do not cache storage location before expanding
Do not cache storage location before expanding

EXPAND_SERIES_TAIL could move the storage, and invalidate the cached
storage pointer. Just save the index and recalcuate the location.

This function seems not to be used until now.

rgchris/ren-c,codebybrett/ren-c,codebybrett/ren-c,draegtun/ren-c,codebybrett/ren-c,codebybrett/ren-c,giuliolunati/ren-c,kealist/ren-c,kealist/ren-c,giuliolunati/ren-c,giuliolunati/ren-c,kealist/ren-c,hostilefork/rebol,hostilefork/rebol,draegtun/ren-c,kealist/ren-c,draegtun/ren-c,codebybrett/ren-c,draegtun/ren-c,kealist/ren-c,kealist/ren-c,hostilefork/rebol,giuliolunati/ren-c,hostilefork/rebol,draegtun/ren-c,giuliolunati/ren-c,rgchris/ren-c,codebybrett/ren-c,rgchris/ren-c,hostilefork/rebol,rgchris/ren-c,draegtun/ren-c,rgchris/ren-c,hostilefork/rebol