Eliminate deprecated Int32/Int64.fromInt() constructors

pkg/fixnum/lib/src/int64.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.
 
 part of fixnum;
 
 /**
  * An immutable 64-bit signed integer, in the range [-2^63, 2^63 - 1].
  * Arithmetic operations may overflow in order to maintain this range.
  */
@@ skipping 130 matching lines @@
     }
 
     if (negative) {
       v0 = _MASK & ~v0;
       v1 = _MASK & ~v1;
       v2 = _MASK2 & ~v2;
     }
     return new Int64._bits(v0, v1, v2);
   }
 
-  /**
-   * Constructs an [Int64] with a given [int] value.
-   */
-  @deprecated
-  factory Int64.fromInt(int value) => new Int64(value);
-
   factory Int64.fromBytes(List<int> bytes) {
     int top = bytes[7] & 0xff;
     top <<= 8;
     top |= bytes[6] & 0xff;
     top <<= 8;
     top |= bytes[5] & 0xff;
     top <<= 8;
     top |= bytes[4] & 0xff;
 
     int bottom = bytes[3] & 0xff;
@@ skipping 872 matching lines @@
       if (r0 == 0 && r1 == 0 && r2 == 0) {
         return ZERO;
       } else {
         return _sub(b0, b1, b2, r0, r1, r2);
       }
     } else {
       return _negate(r0, r1, r2);
     }
   }
 }