Reason for revert:
Jakob found the actual issue with the CL and is going to land the fix after relanding the WB elimination.
Original issue's description:
> Revert of [turbofan] Restore basic write barrier elimination. (patchset #2 id:20001 of https://codereview.chromium.org/1938993002/ )
>
> Reason for revert:
> Breaks WBs that should be there ;)
>
> https://uberchromegw.corp.google.com/i/client.v8/builders/V8%20Linux%20-%20gc%20stress/builds/3305
>
> Will open repro bug asap.
>
> Original issue's description:
> > [turbofan] Restore basic write barrier elimination.
> >
> > Restore the basic write barrier elimination that we used to run as part
> > of the simplified lowering phase (in ChangeLowering actually) before, by
> > moving the write barrier computation to SimplifiedLowering where we can
> > still look at types and consider the heap/isolate, and just update the
> > WriteBarrierKind in the FieldAccess/ElementAccess that we later use when
> > lowering to a machine Load/Store.
> >
> > CQ_INCLUDE_TRYBOTS=tryserver.v8:v8_linux64_tsan_rel
> > R=mstarzinger@chromium.org
> > BUG=v8:4969,chromium:608636
> > LOG=n
> >
> > Committed: https://crrev.com/7dcb6ad379fbacbc8bdc8e11a6e50d680ffa3f62
> > Cr-Commit-Position: refs/heads/master@{#35969}
>
> TBR=mstarzinger@chromium.org,bmeurer@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:4969,chromium:608636
>
> Committed: https://crrev.com/a782e93c617e728cded5ad878de11137a67891b7
> Cr-Commit-Position: refs/heads/master@{#35983}
TBR=mstarzinger@chromium.org,bmeurer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4969,chromium:608636
Review-Url: https://codereview.chromium.org/1943323002
Cr-Commit-Position: refs/heads/master@{#35984}
95b8f3b0d3