[9] Review request for 8032788: ImageIcon constructor throws an NPE and hangs when passed a null String parameter

[anton nashatyrev]

Hello,
    could you please review the following fix:
fix: http://cr.openjdk.java.net/~anashaty/8032788/9/webrev.00/ 
<http://cr.openjdk.java.net/%7Eanashaty/8032788/9/webrev.00/>
bug: https://bugs.openjdk.java.net/browse/JDK-8032788

    Problem: MediaTracker.waitForID() hangs if the Image was created 
with null argument.
      The expected behavior is the same as if the non-existent file 
name is passed, i.e. ERRORED loading status

    Fix: avoid throwing unexpected NPE from FileImageSource.getDecoder()

Thanks!
Anton.