[turbofan] Proper dead code elimination as regular reducer.

test/unittests/compiler/node-test-utils.cc

Index: test/unittests/compiler/node-test-utils.cc
diff --git a/test/unittests/compiler/node-test-utils.cc b/test/unittests/compiler/node-test-utils.cc
index 5d01185e29995b8dcc4bde726780b7a5b1ea739d..27d8ed3f08d2907d6cc0e86073bde8c4a83269f4 100644
--- a/test/unittests/compiler/node-test-utils.cc
+++ b/test/unittests/compiler/node-test-utils.cc
@@ -1378,6 +1378,11 @@ class IsUnopMatcher final : public NodeMatcher {
 }  // namespace
 
 
+Matcher<Node*> IsDead() {
+  return MakeMatcher(new NodeMatcher(IrOpcode::kDead));
+}
+
+
 Matcher<Node*> IsEnd(const Matcher<Node*>& control0_matcher) {
   return MakeMatcher(new IsControl1Matcher(IrOpcode::kEnd, control0_matcher));
 }