1) Add exit point parameter to EmitGenericPropertyStore(),
2) carve TryLookupPropertyInSimpleObject() out of TryLookupProperty().

Bug: v8:5988
Change-Id: I6cef48731c27e5bb72dce5eaa0169fbf59787ed7
Reviewed-on: https://chromium-review.googlesource.com/997747Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52448}