Includes fixes for several ClusterFuzz regressions:

1) fix an invalid Handle-cast in ic.cc (chromium:866282)

2) fix for improper accounting of used/unused inobject
fields, found by clusterfuzz (chromium:866357).

3) fix number of control outputs for the JSCloneObject
operator to be used by IfSuccess and IfException nodes (chromium:866727).

4) fix property constness in out-of-object properties of fast-cloned
object to be compatible with DCHECKs in StoreIC (chromium:866861).

Also includes the fixups missing from the initial commit, and
regression tests

BUG=v8:7611, chromium:866282, chromium:866357, chromium:866727, chromium:866861
R=jkummerow@chromium.org, mvstanton@chromium.org
TBR=rmcilroy@chromium.org

Change-Id: I77220308482f16db2893c0dcebec36530d0f5540
Reviewed-on: https://chromium-review.googlesource.com/1146297
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54706}