[turbofan] Prettify a condition

Change-Id: I3800486f18a3693c9e2d3ace0a6f8ee626efc84e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2289780
Commit-Queue: Georg Neis <neis@chromium.org>
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Auto-Submit: Georg Neis <neis@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68756}

src/compiler/backend/jump-threading.cc

@@ -206,7 +206,7 @@ void JumpThreading::ApplyForwarding(Zone* local_zone,
     if (constant.type() == Constant::kRpoNumber) {
       RpoNumber rpo = constant.ToRpoNumber();
       RpoNumber fw = result[rpo.ToInt()];
-      if (!(fw == rpo)) immediates[i] = Constant(fw);
+      if (fw != rpo) immediates[i] = Constant(fw);
     }
   }