[reg-alloc] Try to use same register after deferred-fixed range

Change-Id: I0dff07c33d55a3e1b8b16e095d771337c51876ba
Bug: v8:9088
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1682029Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62466}

src/compiler/backend/register-allocator.cc

@@ -3477,6 +3477,8 @@ void LinearScanAllocator::UpdateDeferredFixedRanges(SpillMode spill_mode,
               RegisterName(other->assigned_register()));
         LiveRange* split_off =
             other->SplitAt(next_start, data()->allocation_zone());
+        // Try to get the same register after the deferred block.
+        split_off->set_controlflow_hint(other->assigned_register());
         DCHECK_NE(split_off, other);
         AddToUnhandled(split_off);
         update_caches(other);