[turbofan] Don't introduce unnecessary x===true comparisons.

In the JSCallReducer, the lowering for Array#filter(), Array#some() and
Array#every() properly converted the outcome of the predicate call to
boolean using the ToBoolean conversion, but then also added a redundant
ReferenceEqual comparison with true. This particular pattern is not
optimized by TurboFan, since it can never happen using the regular
comparison machinery. So remove the unnecessary ReferenceEqual and just
do the ToBoolean in the JSCallReducer.

Bug: v8:8238
Change-Id: Ic2585431b4b75d3d5f978c85156cfb19738b7ae6
Reviewed-on: https://chromium-review.googlesource.com/c/1267177Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56430}

src/compiler/js-call-reducer.cc

@@ -2162,12 +2162,8 @@ Node* JSCallReducer::DoFilterPostCallbackWork(ElementsKind kind, Node** control,
                                               Node* callback_value) {
   Node* boolean_result =
       graph()->NewNode(simplified()->ToBoolean(), callback_value);
-
-  Node* check_boolean_result =
-      graph()->NewNode(simplified()->ReferenceEqual(), boolean_result,
-                       jsgraph()->TrueConstant());
   Node* boolean_branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
-                                          check_boolean_result, *control);
+                                          boolean_result, *control);
 
   Node* if_true = graph()->NewNode(common()->IfTrue(), boolean_branch);
   Node* etrue = *effect;
@@ -2467,11 +2463,8 @@ Reduction JSCallReducer::ReduceArrayEvery(Node* node,
   {
     Node* boolean_result =
         graph()->NewNode(simplified()->ToBoolean(), callback_value);
-    Node* check_boolean_result =
-        graph()->NewNode(simplified()->ReferenceEqual(), boolean_result,
-                         jsgraph()->TrueConstant());
     Node* boolean_branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
-                                            check_boolean_result, control);
+                                            boolean_result, control);
     if_false_callback = graph()->NewNode(common()->IfFalse(), boolean_branch);
     efalse_callback = effect;
 
@@ -2824,11 +2817,8 @@ Reduction JSCallReducer::ReduceArraySome(Node* node,
   {
     Node* boolean_result =
         graph()->NewNode(simplified()->ToBoolean(), callback_value);
-    Node* check_boolean_result =
-        graph()->NewNode(simplified()->ReferenceEqual(), boolean_result,
-                         jsgraph()->TrueConstant());
     Node* boolean_branch = graph()->NewNode(
-        common()->Branch(BranchHint::kFalse), check_boolean_result, control);
+        common()->Branch(BranchHint::kFalse), boolean_result, control);
     if_true_callback = graph()->NewNode(common()->IfTrue(), boolean_branch);
     etrue_callback = effect;