Elytron Tool filesystem-realm-encrypt tests use incorrect credential store path

The test cases for filesystem-realm-encrypt command reference two potential paths to the credential store:

• ./target/test-classes/filesystem-encrypt/mycredstore.cs
•  ./mycredstore.cs

This results in two different credentials stores being used, including one outside of the tests directory.

Relatedly, one of the commands to run commands in the test cases sets the credential store path twice.