Correct intermittent failures in PasswordBasedEncryptorGroovyTest

PasswordBasedEncryptorGroovyTest can fail intermittently during automated builds.  A recent failure occurred when comparing encrypted and plaintext results:

Error: Failures:
Error: PasswordBasedEncryptorGroovyTest.testBcryptDecryptShouldSupportLegacyKeyDerivationProcess:445 assert recovered == PLAINTEXT

The test class should be evaluated to determine the source of the problem and refactored to avoid potential failures. It is also worth evaluating the opportunity to refactor the test into more discrete test classes.