[DAGCombiner] Simplify code around call to reduceLoadWidth in visitAND. NFC

We were looking for loads or any_extend+load. reduceLoadWidth
hasn't known how to look through such an any_extend to find the
load since D40667 almost 5 years ago.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D130333