Revert of Revert of [AiS] Merge answers into highest-scoring result (patchset #1...

Revert of Revert of [AiS] Merge answers into highest-scoring result (patchset #1 id:1 of https://codereview.chromium.org/598253002/)

Reason for revert:
Broken GN build:
http://build.chromium.org/p/chromium.linux/builders/Linux%20GN%20%28dbg%29/builds/13101

Original issue's description:
> Revert of [AiS] Merge answers into highest-scoring result (patchset #6 id:100001 of https://codereview.chromium.org/584653004/)
>
> Reason for revert:
> The new tests are flaky:
> http://build.chromium.org/p/chromium.memory/builders/Linux%20ASan%20LSan%20Tests%20%283%29/builds/7944
>
> Original issue's description:
> > [AiS] Merge answers into highest-scoring result
> >
> > Answer contents and type must always be copied to the highest-scoring
> > suggestion, to ensure answers are not lost due to suggestion
> > deduplication.
> >
> > BUG=415836
> > R=mpearson
> >
> > Committed: https://crrev.com/978a4bf4a3be714950ed265660bd9566f7abd922
> > Cr-Commit-Position: refs/heads/master@{#296520}
>
> TBR=mpearson@google.com,mpearson@chromium.org,newt@chromium.org,groby@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=415836
>
> Committed: https://crrev.com/ba5d32190d4f056b11738b050b94895b655c52f7
> Cr-Commit-Position: refs/heads/master@{#296555}

TBR=mpearson@google.com,mpearson@chromium.org,newt@chromium.org,groby@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=415836

Review URL: https://codereview.chromium.org/599273002

Cr-Commit-Position: refs/heads/master@{#296573}