Disable 2 intrinsics causing optimizer issues (under investigation).

runtime/vm/intrinsifier_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intrinsifier.h"
 
 #include "vm/assembler.h"
@@ skipping 804 matching lines @@
 
 void Intrinsifier::Bigint_setDigits(Assembler* assembler) {
   __ movq(RAX, Address(RSP, + 1 * kWordSize));
   __ movq(RCX, Address(RSP, + 2 * kWordSize));
   __ StoreIntoObject(RCX,
                      FieldAddress(RCX, Bigint::digits_offset()), RAX, false);
   __ ret();
 }
 
 
-void Intrinsifier::Bigint_add(Assembler* assembler) {
+void Intrinsifier::Bigint_absAdd(Assembler* assembler) {
   // TODO(regis): Implement.
 }
 
 
-void Intrinsifier::Bigint_sub(Assembler* assembler) {
+void Intrinsifier::Bigint_absSub(Assembler* assembler) {
   // TODO(regis): Implement.
 }
 
 
 void Intrinsifier::Bigint_mulAdd(Assembler* assembler) {
   // TODO(regis): Implement.
 }
 
 
 void Intrinsifier::Bigint_sqrAdd(Assembler* assembler) {
@@ skipping 737 matching lines @@
   // Set return value to Isolate::current_tag_.
   __ movq(RAX, Address(RBX, Isolate::current_tag_offset()));
   __ ret();
 }
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64