This reverts commit b9d2c22a.

Reason for revert: Reverting due to regressions in multiple JS
performance/memory benchmarks. 

Original change's description:
> [codegen] Reduce kScratchDoubleReg usage
> 
> Bug: v8:10506
> Change-Id: I3fccaf640e23b5fcc7722164e2437b247684f824
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2207919
> Reviewed-by: Zhi An Ng <zhin@chromium.org>
> Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#67909}

TBR=gdeepti@chromium.org,zhin@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: v8:10506
Change-Id: I9a1c960c577f0e0d42c817d03bc56895268a0718
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2219339Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68031}