Remove bigint reference in js_number.dart

sdk/lib/_internal/compiler/js_lib/js_number.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 _interceptors;
 
 /**
  * The super interceptor class for [JSInt] and [JSDouble]. The compiler
  * recognizes this class as an interceptor, and changes references to
  * [:this:] to actually use the receiver of the method, which is
@@ skipping 397 matching lines @@
       e ~/= 2;
       b = (b * b) % m;
     }
     return r;
   }
 
   // Returns 1/this % m, with m > 0.
   int modInverse(int m) {
     if (m is! int) throw new ArgumentError(m);
     if (m <= 0) throw new RangeError(m);
-    if (m is _Bigint) {
-      return _toBigint().modInverse(m);
-    }
     bool ac = m.isEven;
     int u = m;
     int v = this;
     int a = 1,
         b = 0,
         c = 0,
         d = 1;
     while (u != 0) {
       while (u.isEven) {
         u ~/= 2;
@@ skipping 85 matching lines @@
 }
 
 class JSDouble extends JSNumber implements double {
   const JSDouble();
   Type get runtimeType => double;
 }
 
 class JSPositiveInt extends JSInt {}
 class JSUInt32 extends JSPositiveInt {}
 class JSUInt31 extends JSUInt32 {}