Code Review Request, JDK-8213577, Update the default SSL session cache size to 20480

[Xuelei Fan]

Hi,

Please review this simple update:
     http://cr.openjdk.java.net/~xuelei/8210985/webrev.00/

The default value for the maximum number of entries in the SSL session 
cache (SSLSessionContext.getSessionCacheSize()) is infinite now.  In the 
request, the default value is updated to 20480 for performance 
consideration.

For the detailed behavior update, please refer to CSR:
     https://bugs.openjdk.java.net/browse/JDK-8213577

Thanks,
Xuelei