RFR 8207250: setUseClientMode post handshake with the same value as before does not throw IAE

[Weijun Wang]

Please take a review at

   JBS: https://bugs.openjdk.java.net/browse/JDK-8207250
   Fix: http://cr.openjdk.java.net/~weijun/8207250/webrev.00/

The status check should be performed no matter what the argument is.

Thanks
Max