Reland of [turbofan] Introduce proper JSCreateLiteralRegExp operator. (patchset #1 id:1 of https://codereview.chromium.org/1472423002/ )

Reason for revert:
[Sheriff] Wrong revert.

Original issue's description:
> Revert of [turbofan] Introduce proper JSCreateLiteralRegExp operator. (patchset #2 id:20001 of https://codereview.chromium.org/1475973002/ )
>
> Reason for revert:
> Broke "V8 Linux64 GC Stress - custom snapshot".
>
> http://build.chromium.org/p/client.v8/builders/V8%20Linux64%20GC%20Stress%20-%20custom%20snapshot/builds/2824
>
> Original issue's description:
> > [turbofan] Introduce proper JSCreateLiteralRegExp operator.
> >
> > This adds a new JavaScript level operator for regexp literal creation,
> > similar to what we already have for array and object literals. This
> > once gets lowered to a call to the FastCloneRegExpStub always.
> >
> > R=mstarzinger@chromium.org
> >
> > Committed: https://crrev.com/8659c5d1d287177369ce179a8d0b910192d840d9
> > Cr-Commit-Position: refs/heads/master@{#32288}
>
> TBR=mstarzinger@chromium.org,bmeurer@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
>
> Committed: https://crrev.com/168683d270d44f05f28acaf7d34c32d0250d2a4c
> Cr-Commit-Position: refs/heads/master@{#32292}

TBR=mstarzinger@chromium.org,bmeurer@chromium.org,ishell@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1478823002

Cr-Commit-Position: refs/heads/master@{#32293}