debug: remote debugging skips shutting down ProtocolServer

[polinasok]

We should see the following logging at the end of a debug session as it calls super.disconnectRequest:

DisconnectRequest to parent
DisconnectResponse

These do not show up in remote logs because in that case close() returns without resolving a promise (code), so the rest of the exit code awaits. Vscode just has a disconnect timeout, but according to @quoctruong, Theia does not.

[gopherbot]

Change https://golang.org/cl/257337 mentions this issue: debugAdapter: Fix bugs that cause remote debug to hang