[turbofan] Change the way nodes with multiple outputs are verified.

With the original implementation nodes which were not reachable from end
could cause the verification to fail.

R=titzer@chromium.org, mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/1782863002

Cr-Commit-Position: refs/heads/master@{#34683}

src/compiler/verifier.cc

@@ -135,6 +135,11 @@ void Verifier::Visitor::Check(Node* node) {
     CheckOutput(value, node, value->op()->ValueOutputCount(), "value");
     CHECK(IsDefUseChainLinkPresent(value, node));
     CHECK(IsUseDefChainLinkPresent(value, node));
+    // Verify that only parameters and projections can have input nodes with
+    // multiple outputs.
+    CHECK(node->opcode() == IrOpcode::kParameter ||
+          node->opcode() == IrOpcode::kProjection ||
+          value->op()->ValueOutputCount() <= 1);
   }
 
   // Verify all context inputs are value nodes.
@@ -161,16 +166,6 @@ void Verifier::Visitor::Check(Node* node) {
     CHECK(IsUseDefChainLinkPresent(control, node));
   }
 
-  // Verify all successors are projections if multiple value outputs exist.
-  if (node->op()->ValueOutputCount() > 1) {
-    for (Edge edge : node->use_edges()) {
-      Node* use = edge.from();
-      CHECK(!NodeProperties::IsValueEdge(edge) ||
-            use->opcode() == IrOpcode::kProjection ||
-            use->opcode() == IrOpcode::kParameter);
-    }
-  }
-
   switch (node->opcode()) {
     case IrOpcode::kStart:
       // Start has no inputs.