[9] RFR: 8048622: Enhance tests for PKCS11 keystores with NSS

[Artem Smotrakov]

Hello,

Please review a couple of changes for PKCS11 tests:
- Added a new test which checks that a keystore can't be loaded with 
incorrect password,
   found https://bugs.openjdk.java.net/browse/JDK-8134232
- Added a check that a trusted entry can be removedfrom keystore
- Updated existing tests not to use random data
- Updated existing tests to use try-with-resources for I/O 
operationswith files
- Small cosmetic updates

Bug: https://bugs.openjdk.java.net/browse/JDK-8048622
Webrev: http://cr.openjdk.java.net/~asmotrak/8048622/webrev.00/

Artem