The dispatcher is responsible for handling stores to lexical environment
variables and for storing directly to the JSGlobalObject. In the latter
case the dispatcher also ensures that JSGlobalProxy is provided as
a receiver if a setter function has to be called.
Unlike StoreIC the calling convention for the StoreGlobalIC does not include
receiver.

Bug: v8:7206, chromium:576312, v8:5561
Change-Id: Ifa896c7b41bf440785b757c2272ec91211e79c98
Reviewed-on: https://chromium-review.googlesource.com/818965
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50081}