[turbofan] Introduces another DCHECK in the register allocator.

The previous DCHECK (removed in issue 2316033002) was checking that the new interval strictly overlapped with the first interval.

BUG=

Review-Url: https://codereview.chromium.org/2321113002
Cr-Commit-Position: refs/heads/master@{#39290}

src/compiler/register-allocator.cc

@@ -1114,6 +1114,10 @@ void TopLevelLiveRange::AddUseInterval(LifetimePosition start,
       interval->set_next(first_interval_);
       first_interval_ = interval;
     } else {
+      // Order of instruction's processing (see ProcessInstructions) guarantees
+      // that each new use interval either precedes, intersects with or touches
+      // the last added interval.
+      DCHECK(start <= first_interval_->end());
       first_interval_->set_start(Min(start, first_interval_->start()));
       first_interval_->set_end(Max(end, first_interval_->end()));
     }