[regalloc] Enable control-flow aware allocation

We enable this feature to collect performance data; revert at will.

Bug: v8:9088
Change-Id: I57cd79707fe56ec5a2d6d5ee65b7ce24bda57773
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1585726
Auto-Submit: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61117}

src/flag-definitions.h

@@ -439,7 +439,7 @@ DEFINE_BOOL(print_deopt_stress, false, "print number of possible deopt points")
 // Flags for TurboFan.
 DEFINE_BOOL(turbo_sp_frame_access, false,
             "use stack pointer-relative access to frame wherever possible")
-DEFINE_BOOL(turbo_control_flow_aware_allocation, false,
+DEFINE_BOOL(turbo_control_flow_aware_allocation, true,
             "consider control flow while allocating registers")
 
 DEFINE_STRING(turbo_filter, "*", "optimization filter for TurboFan compiler")