For stores with Double feedback, StoreIC needs to check that the
representation is still Double before doing the store, in case it
accidentally tries to write to an object or worse, mutate a non-mutable
HeapNumber.

Bug: v8:9606
Bug: chromium:997485
Change-Id: I51e0953b40f752648c5e86b8644c23baf636367e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1768373
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63402}