[turbofan] Finish support for holey double elements backing stores.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index f62fad6ed6c6a0ac9a474fbf9e76bde710ff7ff4..9c2e3151c5a1dc6b3ec44d11122f13787a59c136 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -1677,6 +1677,11 @@ Type* Typer::Visitor::TypeNumberToUint32(Node* node) {
 }
 
 
+Type* Typer::Visitor::TypeNumberIsHoleNaN(Node* node) {
+  return Type::Boolean(zone());
+}
+
+
 Type* Typer::Visitor::TypePlainPrimitiveToNumber(Node* node) {
   return TypeUnaryOp(node, ToNumber);
 }