Revert of [turbofan] Splinter into one range.

Revert of [turbofan] Splinter into one range. (patchset #2 id:80001 of https://codereview.chromium.org/1391023007/ )

Reason for revert:
Weird endless loop in TopLevelLiveRange::Merge() due to always splitting first and not making progress. See comments, unfortunately no useable repro.

Original issue's description:
> [turbofan] Splinter into one range.
>
> Before this CL, we created one live range per successive set of
> deferred blocks. For scenarios with many such blocks, this creates
> an upfront pressure for the register allocator to deal with many ranges.
> Linear sorts ranges, which is a super-linear operation.
>
> The change places all deferred intervals into one range, meaning that,
> at most, there will be twice as many live ranges as the original set. In
> pathological cases (benchmarks/Compile/slow_nbody1.js), this change
> halves the compilation time. We see some improvements elsewhere,
> notably SQLite at ~4-5%.
>
> We may be able to avoid the subsequent merge. Its cost is the
> additional ranges it may need to create. The sole reason for the merge
> phase is to provide an unchanged view of the world to the subsequent
> phases. With the at-most-one splinter model, we may be able to teach
> the other phases about splintering - should we find perf hindrances
> due to merging.
>
> Committed: https://crrev.com/efdcd20267870276c5824f1ccf4e171ac378f7ae
> Cr-Commit-Position: refs/heads/master@{#31224}

TBR=jarin@chromium.org,mtrofin@google.com,mtrofin@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/23a8837fcc8a212a4a2608a9bf53f908a7a91728
Cr-Commit-Position: refs/heads/master@{#31300}

[Benedikt Meurer, 2015-10-15 13:27:46]

Created Revert of [turbofan] Splinter into one range.

[commit-bot: I haz the power, 2015-10-15 13:28:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1403163003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1403163003/1

[commit-bot: I haz the power, 2015-10-15 13:28:14]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-15 13:28:28]

Patchset 1 (id:??) landed as
https://crrev.com/23a8837fcc8a212a4a2608a9bf53f908a7a91728
Cr-Commit-Position: refs/heads/master@{#31300}