Process two 32-bit digits as one 64-bit digit in all bigint intrinsics on x64.

tests/lib/mirrors/invocation_fuzz_test.dart

 // Copyright (c) 2014, 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.
 
 // This test reflectively enumerates all the methods in the system and tries to
 // invoke them will various basic values (nulls, ints, etc). This may result in

[zra, 2015/01/05 16:39:22]

will -> with

[regis, 2017/01/13 02:34:46]

Done.

 // Dart exceptions or hangs, but should never result in crashes or JavaScript
 // exceptions.
 
 library test.invoke_natives;
 
 import 'dart:mirrors';
 import 'dart:async';
 
 // Methods to be skipped, by qualified name.
 var blacklist = [
+  // TODO(regis): investigate.
+  'dart.core._Montgomery._invDigitPair',
+
   // Don't recurse on this test.
   'test.invoke_natives',
 
   // Don't exit the test pre-maturely.
   'dart.io.exit',
 
   // Don't change the exit code, which may fool the test harness.
   'dart.io.exitCode',
 
   // Don't run blocking io calls.
@@ skipping 148 matching lines @@
      0, 0xEFFFFFF, 0xFFFFFFFF, 0xFFFFFFFFFFFFFFFF, 3.14159,
      "foo", 'blåbærgrød', 'Îñţérñåţîöñåļîžåţîờñ', "𝄞", #symbol];
   valueObjects.forEach((v) => checkInstance(reflect(v), 'value object'));
 
   uncaughtErrorHandler(self, parent, zone, error, stack) {};
   var zoneSpec =
      new ZoneSpecification(handleUncaughtError: uncaughtErrorHandler);
   testZone = Zone.current.fork(specification: zoneSpec);
   testZone.createTimer(Duration.ZERO, doOneTask);
 }