[lldb-dap] Improving tests logging to understand CI failures. (#139311)

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.

0 files changed, 0 insertions, 0 deletions