[turbofan] Drop the obsolete TypeGuard operator.

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

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_UNITTESTS_COMPILER_NODE_TEST_UTILS_H_
 #define V8_UNITTESTS_COMPILER_NODE_TEST_UTILS_H_
 
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/type-hints.h"
 #include "src/machine-type.h"
@@ skipping 408 matching lines @@
                                const Matcher<Node*>& rhs_matcher);
 Matcher<Node*> IsWord32PairShr(const Matcher<Node*>& lhs_matcher,
                                const Matcher<Node*>& mid_matcher,
                                const Matcher<Node*>& rhs_matcher);
 
 Matcher<Node*> IsWord32PairSar(const Matcher<Node*>& lhs_matcher,
                                const Matcher<Node*>& mid_matcher,
                                const Matcher<Node*>& rhs_matcher);
 
 Matcher<Node*> IsStackSlot();
-Matcher<Node*> IsTypeGuard(const Matcher<Type*>& type_matcher,
-                           const Matcher<Node*>& value_matcher,
-                           const Matcher<Node*>& control_matcher);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_UNITTESTS_COMPILER_NODE_TEST_UTILS_H_