Revert "[regalloc] Enable control-flow aware allocation"

This reverts commit d0c980e1.

Reason for revert: Regressions: https://chromeperf.appspot.com/group_report?rev=63641

Original change's description:
> [regalloc] Enable control-flow aware allocation
> 
> This is meant to check the performance impact of:
> https://chromium-review.googlesource.com/c/v8/v8/+/1776085/3
> 
> R=​neis@chromium.org
> 
> Bug: v8:9088
> Change-Id: I8aad5272c1427b8bcaca02bdd0e51bf2779f7451
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1781054
> Reviewed-by: Georg Neis <neis@chromium.org>
> Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63641}

TBR=neis@chromium.org,thibaudm@chromium.org

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

Bug: v8:9088
Change-Id: I8228de030b8ea1066e4a26516d66517dc1dc6ca4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1798684Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63707}

src/flags/flag-definitions.h

@@ -506,7 +506,7 @@ DEFINE_BOOL(print_deopt_stress, false, "print number of possible deopt points")
 DEFINE_BOOL(opt, true, "use adaptive optimizations")
 DEFINE_BOOL(turbo_sp_frame_access, false,
             "use stack pointer-relative access to frame wherever possible")
-DEFINE_BOOL(turbo_control_flow_aware_allocation, true,
+DEFINE_BOOL(turbo_control_flow_aware_allocation, false,
             "consider control flow while allocating registers")
 
 DEFINE_STRING(turbo_filter, "*", "optimization filter for TurboFan compiler")