[regalloc] Stop search for intersections earlier

When looking for intersections between the current range and inactive
range, we can stop the search as soon as the inactive range's next start
is past the current range's end position. We know that subsequent
inactive ranges cannot intersect either, because they are ordered by
their next start.

R=sigurds@chromium.org

Bug: chromium:986862
Change-Id: I249a781be281abc7b438f31848f5d6cb3a25303f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2821434Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73932}

src/compiler/backend/register-allocator.cc

@@ -3958,7 +3958,8 @@ void LinearScanAllocator::FindFreeRegistersForRange(
       // interesting to this range anyway.
       // TODO(mtrofin): extend to aliased ranges, too.
       if ((kSimpleFPAliasing || !check_fp_aliasing()) &&
-          positions[cur_reg] <= cur_inactive->NextStart()) {
+          (positions[cur_reg] <= cur_inactive->NextStart() ||
+           range->End() <= cur_inactive->NextStart())) {
         break;
       }
       LifetimePosition next_intersection =