Reland of [turbofan] Implicitly emit eager checkpoint at graph building. (patchset #1 id:1 of https://codereview.chromium.org/2104973004/ )

Reason for revert:
Can be cleanly relanded without any changes after a fix to redundancy elimination. Kudos go to Benedikt.

Depends on: https://codereview.chromium.org/2112463002/

Original issue's description:
> Revert of [turbofan] Implicitly emit eager checkpoint at graph building. (patchset #13 id:260001 of https://codereview.chromium.org/2074703002/ )
>
> Reason for revert:
> Causers flaky failures on the waterfall on Mac with the following error in the builtin QuickSort method:
>
> #
> # Fatal error in Zone
> # Allocation failed - process out of memory
> #
>
> Original issue's description:
> > [turbofan] Implicitly emit eager checkpoint at graph building.
> >
> > This makes preparation of eager checkpoints within the graph builder
> > implicit. Every sub-expression visitation is now guaranteed to emit
> > valid checkpoints in AstContext.
> >
> > R=jarin@chromium.org
> > BUG=v8:5021
> >
> > Committed: https://crrev.com/74e328efee7995aeee6d568f9d14f9bbc1087100
> > Cr-Commit-Position: refs/heads/master@{#37368}
>
> TBR=jarin@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:5021
>
> Committed: https://crrev.com/45190a4fbfa5199f6ddf5ed9a7e2f50be865e0db
> Cr-Commit-Position: refs/heads/master@{#37372}

TBR=jarin@chromium.org
BUG=v8:5021

Review-Url: https://codereview.chromium.org/2107163002
Cr-Commit-Position: refs/heads/master@{#37395}