More type checking performance improvements and a bug fix in intrinsifier.

runtime/vm/intrinsifier_ia32.cc

Index: runtime/vm/intrinsifier_ia32.cc
===================================================================
--- runtime/vm/intrinsifier_ia32.cc	(revision 5913)
+++ runtime/vm/intrinsifier_ia32.cc	(working copy)
@@ -246,11 +246,11 @@
     __ movl(EBX, Address(ESP, + 3 * kWordSize));  // Array.
     __ movl(EBX, FieldAddress(EBX, type_args_field_offset));
     // EBX: Type arguments of array.
-    __ movl(EAX, FieldAddress(EBX, Object::class_offset()));
+    __ cmpl(EBX, raw_null);
+    __ j(EQUAL, &checked_ok, Assembler::kNearJump);
     // Check if it's Dynamic.
-    __ cmpl(EAX, raw_null);
-    __ j(EQUAL, &checked_ok, Assembler::kNearJump);
     // For now handle only TypeArguments and bail out if InstantiatedTypeArgs.
+    __ movl(EAX, FieldAddress(EBX, Object::class_offset()));
     __ CompareObject(EAX, Object::ZoneHandle(Object::type_arguments_class()));
     __ j(NOT_EQUAL, &fall_through, Assembler::kNearJump);
     // Get type at index 0.