[turbofan] Turn off lowering to kFindOrderedHashMapEntryForInt32Key.

As a simple and backmergeable fix for crbug.com/774459.

Bug: chromium:774459
Tbr: bmeurer@chromium.org
Change-Id: Ibe55ad13fe6be63a76dc3079a0288356ce35de9f
Reviewed-on: https://chromium-review.googlesource.com/719461
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48561}

src/compiler/simplified-lowering.cc

@@ -2933,19 +2933,8 @@ class RepresentationSelector {
         return SetOutput(node, MachineRepresentation::kTagged);
 
       case IrOpcode::kFindOrderedHashMapEntry: {
-        Type* const key_type = TypeOf(node->InputAt(1));
-        if (key_type->Is(Type::Signed32())) {
-          VisitBinop(node, UseInfo::AnyTagged(), UseInfo::TruncatingWord32(),
-                     MachineRepresentation::kWord32);
-          if (lower()) {
-            NodeProperties::ChangeOp(
-                node,
-                lowering->simplified()->FindOrderedHashMapEntryForInt32Key());
-          }
-        } else {
-          VisitBinop(node, UseInfo::AnyTagged(),
-                     MachineRepresentation::kTaggedSigned);
-        }
+        VisitBinop(node, UseInfo::AnyTagged(),
+                   MachineRepresentation::kTaggedSigned);
         return;
       }