Unify handling of identical(NaN, NaN) between generated code and Dart API.

runtime/vm/object_test.cc

Index: runtime/vm/object_test.cc
===================================================================
--- runtime/vm/object_test.cc	(revision 37108)
+++ runtime/vm/object_test.cc	(working copy)
@@ -527,7 +527,11 @@
     EXPECT(nan0.IsIdenticalTo(nan0));
     EXPECT(nan0.CanonicalizeEquals(nan0));
     EXPECT(!nan0.OperatorEquals(nan0));
-    // TODO(18738): Test bitwise different NaNs after agreement on spec.
+    const Double& nan1 = Double::Handle(Double::New(0.0/0.0));
+    const Double& nan2 = Double::Handle(Double::New(1.0/0.0));

[koda, 2014/06/06 23:26:29]

Doesn't 1.0/0.0 give you positive infinity?

It seems better to to a reinterpret_cast here from two explicit bit patterns.

[regis, 2014/06/06 23:51:56]

Yes, thank you, 1.0/0.0 is infinity, but not a NaN.
I've added isnan checks and explicit bit patterns.

+    EXPECT(!nan1.IsIdenticalTo(nan2));
+    EXPECT(!nan1.CanonicalizeEquals(nan2));
+    EXPECT(!nan1.OperatorEquals(nan2));
   }
   {
     const String& dbl_str0 = String::Handle(String::New("bla"));