[scalar-lowering][wasm-simd] Remove unnecessary equal

We are comparing equals to 0, we can remove this equality comparison,
and invert the phi outputs. This saves 1 op/node for every lowered
comparision.

Bug: v8:10824
Change-Id: I4957bed635c34d47fff98c5556ab55754d3fd91e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2391911Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69702}

src/compiler/simd-scalar-lowering.cc

@@ -687,15 +687,13 @@ void SimdScalarLowering::LowerCompareOp(Node* node, SimdType input_rep_type,
     } else {
       cmp_result = graph()->NewNode(op, rep_left[i], rep_right[i]);
     }
-    Diamond d_cmp(graph(), common(),
-                  graph()->NewNode(machine()->Word32Equal(), cmp_result,
-                                   mcgraph_->Int32Constant(0)));
+    Diamond d_cmp(graph(), common(), cmp_result);
     MachineRepresentation rep =
         (input_rep_type == SimdType::kFloat32x4)
             ? MachineRepresentation::kWord32
             : MachineTypeFrom(input_rep_type).representation();
     rep_node[i] =
-        d_cmp.Phi(rep, mcgraph_->Int32Constant(0), mcgraph_->Int32Constant(-1));
+        d_cmp.Phi(rep, mcgraph_->Int32Constant(-1), mcgraph_->Int32Constant(0));
   }
   ReplaceNode(node, rep_node, num_lanes);
 }