[turbofan] Introduce CheckIf simplified operator.

src/compiler/node-matchers.h

Index: src/compiler/node-matchers.h
diff --git a/src/compiler/node-matchers.h b/src/compiler/node-matchers.h
index 93c091dc8a6869fa9c73f3892e16b0f6f9ac2d34..d6d0615150dcb0dec114a3adb9c8e643c23328c8 100644
--- a/src/compiler/node-matchers.h
+++ b/src/compiler/node-matchers.h
@@ -172,6 +172,10 @@ struct HeapObjectMatcher final
     : public ValueMatcher<Handle<HeapObject>, IrOpcode::kHeapConstant> {
   explicit HeapObjectMatcher(Node* node)
       : ValueMatcher<Handle<HeapObject>, IrOpcode::kHeapConstant>(node) {}
+
+  bool Is(Handle<HeapObject> const& value) const {
+    return this->HasValue() && this->Value().address() == value.address();
+  }
 };