Adds thrift HSHA test for CASSANDRA-6285
update jna path for thrift_hsha_test
skip thrift_hsha_test if JNA not found.
Adds test for CASSANDRA-6546 - thrift connections not being closed
modification to fix cygwin on windows
Merge branch 'Windows' of https://github.com/josh-mckenzie/cassandra-dtest into Windows