[turbofan] Handle void return in simplified-lowering.cc.

R=jarin@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1296933002

Cr-Commit-Position: refs/heads/master@{#30197}

src/compiler/simplified-lowering.cc

@@ -430,7 +430,11 @@ class RepresentationSelector {
       }
     }
 
-    SetOutput(node, desc->GetMachineSignature()->GetReturn());
+    if (sig->return_count() > 0) {
+      SetOutput(node, desc->GetMachineSignature()->GetReturn());
+    } else {
+      SetOutput(node, kMachAnyTagged);
+    }
   }
 
   void VisitStateValues(Node* node) {