VM: Remove _leftShiftWithMask32.

runtime/lib/integers.dart

 // Copyright (c) 2012, 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.
 
 abstract class _IntegerImplementation {
   // The Dart class _Bigint extending _IntegerImplementation requires a
   // default constructor.
 
   Type get runtimeType => int;
 
@@ skipping 245 matching lines @@
     _OneByteString string = _OneByteString._allocate(length);
     string._setAt(0, 0x2d);  // '-'. Is overwritten if not negative.
     var mask = radix - 1;
     do {
       string._setAt(--length, _digits.codeUnitAt(value & mask));
       value >>= bitsPerDigit;
     } while (value > 0);
     return string;
   }
 
-  _leftShiftWithMask32(count, mask)  native "Integer_leftShiftWithMask32";
-
   // Returns pow(this, e) % m.
   int modPow(int e, int m) {
     if (e is! int) {
       throw new ArgumentError.value(e, "exponent", "not an integer");
     }
     if (m is! int) {
       throw new ArgumentError.value(m, "modulus", "not an integer");
     }
     if (e < 0) throw new RangeError.range(e, 0, null, "exponent");
     if (m <= 0) throw new RangeError.range(m, 1, null, "modulus");
@@ skipping 337 matching lines @@
   // Shift by mint exceeds range that can be handled by the VM.
   int _shrFromInt(int other) {
     if (other < 0) {
       return -1;
     } else {
       return 0;
     }
   }
   int _shlFromInt(int other) native "Mint_shlFromInt";
 }