KillAndHowBeforeEachTestExt scope is sketchy

[eeverman]

KillAndHowBeforeEachTestExt uses class-level storage and operates at the test method level. This is probably just fine in this case, but it would be easier to follow the standard pattern established. working at the same storage and operation level would avoid any unexpected side effects as well and sync it up w/ the ExtensionType enum marker.