DevTools: Use toISOString instead of toGMTString for dates.

Source/devtools/front_end/resources/DirectoryContentView.js

 /*
  * Copyright (C) 2012 Google Inc. 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
@@ skipping 158 matching lines @@
         const indexes = WebInspector.DirectoryContentView.columnIndexes;
         if (errorCode !== 0)
             return;
 
         this._metadata = metadata;
         var data = this.data;
         if (this._entry.isDirectory)
             data[indexes.Size] = WebInspector.UIString("-");
         else
             data[indexes.Size] = Number.bytesToString(metadata.size);
-        data[indexes.ModificationTime] = new Date(metadata.modificationTime).toGMTString();
+        data[indexes.ModificationTime] = new Date(metadata.modificationTime).toISOString();
         this.data = data;
     },
 
     __proto__: WebInspector.DataGridNode.prototype
 }