BZ997421 - Added IBM's JDK specific keystore

- Changed the TestJCASymmetricCodec#testDefaultCodec to load a different keystore in case we are running on an IBM JDK. This is because IBM JDK cannot open a keystore created with SunJCE.
- Changed the TestJCASymmetricCodec#testCodecWithGeneratedKey to generate a keystore at every run. While this might slow things a bit for the second run of this test, this is required as the keystore might have been created by a different JVM.