Apply numeric casts correctly in typed arrays and related code.

src/arraybuffer.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 38 matching lines @@
 }
 
 // ES6 Draft 15.13.5.5.3
 function ArrayBufferSlice(start, end) {
   if (!IS_ARRAYBUFFER(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['ArrayBuffer.prototype.slice', this]);
   }
 
   var relativeStart = TO_INTEGER(start);
+  if (!IS_UNDEFINED(end)) {
+    end = TO_INTEGER(end);
+  }
   var first;
   var byte_length = %ArrayBufferGetByteLength(this);
   if (relativeStart < 0) {
     first = MathMax(byte_length + relativeStart, 0);
   } else {
     first = MathMin(relativeStart, byte_length);
   }
-  var relativeEnd = IS_UNDEFINED(end) ? byte_length : TO_INTEGER(end);
+  var relativeEnd = IS_UNDEFINED(end) ? byte_length : end;
   var fin;
   if (relativeEnd < 0) {
     fin = MathMax(byte_length + relativeEnd, 0);
   } else {
     fin = MathMin(relativeEnd, byte_length);
   }
 
   if (fin < first) {
     fin = first;
   }
@@ skipping 24 matching lines @@
   InstallFunctions($ArrayBuffer, DONT_ENUM, $Array(
       "isView", ArrayBufferIsView
   ));
 
   InstallFunctions($ArrayBuffer.prototype, DONT_ENUM, $Array(
       "slice", ArrayBufferSlice
   ));
 }
 
 SetUpArrayBuffer();