[intrinsics] Remove the %_IsDate intrinsic.

src/crankshaft/hydrogen.cc

Index: src/crankshaft/hydrogen.cc
diff --git a/src/crankshaft/hydrogen.cc b/src/crankshaft/hydrogen.cc
index f26c44e939f7c0298349b40e08405a788f4b7376..4491f3bb44ac4a84eb8b35d54897cf2ef6631610 100644
--- a/src/crankshaft/hydrogen.cc
+++ b/src/crankshaft/hydrogen.cc
@@ -12480,16 +12480,6 @@ void HOptimizedGraphBuilder::GenerateValueOf(CallRuntime* call) {
 }
 
 
-void HOptimizedGraphBuilder::GenerateIsDate(CallRuntime* call) {
-  DCHECK_EQ(1, call->arguments()->length());
-  CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
-  HValue* value = Pop();
-  HHasInstanceTypeAndBranch* result =
-      New<HHasInstanceTypeAndBranch>(value, JS_DATE_TYPE);
-  return ast_context()->ReturnControl(result, call->id());
-}
-
-
 void HOptimizedGraphBuilder::GenerateOneByteSeqStringSetChar(
     CallRuntime* call) {
   DCHECK(call->arguments()->length() == 3);