Fix launch on Windows after CASSANDRA-9615
Fix launch on Windows after CASSANDRA-9615

* Change windows launch to use node cassandra.ps1.
* Remove VerifyPortsAreAvailable on Windows startup
* Fix a flake8 violation in node.py

bcantoni/ccm,pcmanus/ccm,tolbertam/ccm,mike-tr-adamson/ccm,mikefero/ccm,pombredanne/ccm,AtwooTM/ccm,jorgebay/ccm,tolbertam/ccm,bcantoni/ccm,thobbs/ccm,mikefero/ccm,pcmanus/ccm,unusedPhD/ccm,kishkaru/ccm,pcmanus/ccm,thobbs/ccm,mike-tr-adamson/ccm,mike-tr-adamson/ccm