Separate message parsing and message handling into separate threads.
Remove nested message handling in request handlers via `yield`, since it is incompatible with the new split model, and replace it with NO_RESPONSE and Request.respond() to defer responses until later.
Change Message.cant_handle() and Message.isnt_valid() to respond to the request and return the exception, instead of raising it, to accommodate NO_RESPONSE scenarios where a failure needs to be reported later.
Fix#1678: Do not rely on "processId" being returned by "runInTerminal" request
Extract debuggee PID from the "process" event sent by the debug server.
Fix#1679: "exited" event sometimes reports "exitCode": null
Report it as -1 if it cannot be retrieved from the debuggee process.
Fix#1680: Fatal errors in message loop do not fail fast
os._exit() immediately if a fatal error occurs in message parsing or message handling background threads.
* Update ANY to some
* Refactor breakpoint lines in tests
* Replace old import and emable debug with debug_me
* Remove unused code
* Fix some linter issues
* Change from some.such_that to some.str.such_that
* Linting with black
