When adding or overwriting properties of an object, the generic
keyed store stub must check if that property's name might have
an associated protector (e.g. the ArraySpeciesProtector) and
take the slow path if so to ensure that the protector is updated
as needed.
BUG=v8:6269
Review-Url: https://codereview.chromium.org/2821213004
Cr-Commit-Position: refs/heads/master@{#44726}
