The don't currently work (and they're also not particularly useful,
since all of the remote stuff happens inside lldb).
This saves us from annotating tests one by one.
The `EventThreadFunction` can end up calling `HandleCommand`
concurrently with the main request processing thread. The underlying API
does not appear to be thread safe, so add a narrowly scoped mutex lock
to prevent calling it in this place from more than one thread.
Fixes#81686. Prior to this, TestDAP_launch.py is 4% flaky. After, it
passes in 1000 runs.
This adds support for optionally prefixing any command with `?` and/or
`!`.
- `?` prevents the output of a commands to be printed to the console
unless it fails.
- `!` aborts the dap if the command fails.
They come in handy when programmatically running commands on behalf of
the user without wanting them to know unless they fail, or when a
critical setup is required as part of launchCommands and it's better to
abort on failures than to silently skip.
