RFR 8054536: sun.security.x509.Extension object may throw NPE for hashCode and equals method

[Svetlana Nikandrova]

Hello,

please review the fix for:
https://bugs.openjdk.java.net/browse/JDK-8054536
Webrev:
http://cr.openjdk.java.net/~snikandrova/8054536/webrev.00/ 
<http://cr.openjdk.java.net/%7Esnikandrova/8054536/webrev.00/>

Description:
Equals and hasCode methods of Extension use extensionId without prior 
check for "null" (+ 1 mistype in equals javadoc).

Thank you,
Svetlana