[turbofan] Reuse forward fixpoint algorithm in Typer by making it a Reducer.

src/compiler/node-properties-inl.h

Index: src/compiler/node-properties-inl.h
diff --git a/src/compiler/node-properties-inl.h b/src/compiler/node-properties-inl.h
index 5fe0cb6bedb6b8112c469e7a6716bb8987ecaed7..1ff0938f3f42f73af49476aac3b41df8dcef8ab2 100644
--- a/src/compiler/node-properties-inl.h
+++ b/src/compiler/node-properties-inl.h
@@ -201,6 +201,11 @@ inline Bounds NodeProperties::GetBounds(Node* node) {
   return node->bounds();
 }
 
+inline void NodeProperties::RemoveBounds(Node* node) {
+  Bounds empty;
+  node->set_bounds(empty);
+}
+
 inline void NodeProperties::SetBounds(Node* node, Bounds b) {
   DCHECK(b.lower != NULL && b.upper != NULL);
   node->set_bounds(b);