[turbofan] Turn common Guard operator into simplified TypeGuard.

src/compiler/common-operator.h

Index: src/compiler/common-operator.h
diff --git a/src/compiler/common-operator.h b/src/compiler/common-operator.h
index cb3a5154a11b0273e18c0e70ded8c042a022e8b3..c2a7a37a08122b1c8111e9b375f1410b6e8bde90 100644
--- a/src/compiler/common-operator.h
+++ b/src/compiler/common-operator.h
@@ -12,10 +12,6 @@
 
 namespace v8 {
 namespace internal {
-
-// Forward declarations.
-class Type;
-
 namespace compiler {
 
 // Forward declarations.
@@ -191,7 +187,6 @@ class CommonOperatorBuilder final : public ZoneObject {
                       int value_input_count);
   const Operator* EffectPhi(int effect_input_count);
   const Operator* CheckPoint();
-  const Operator* Guard(Type* type);
   const Operator* BeginRegion();
   const Operator* FinishRegion();
   const Operator* StateValues(int arguments);