To improve logging this adjusts two properties of the existing tests:
* Forwards stderr from lldb-dap to the process in case errors are
reported to stderr.
* Adjusts `DebugAdapterServer.terminate` to close stdin and wait for the
process to exit instead of sending SIGTERM. Additionally, if we end up
with a non-zero exit status we now raise an error to note the unexpected
exit status.
With these changes, I did find one test case in
`TestDAP_console.test_diagnositcs` that was not waiting to ensure the
expected event had arrived by the time it performed an assert.
1a0b82563f