Update the servertest package to support connecting to a jsonrpc2 server
using either TCP or io.Pipes. The latter is provided so that regtests
can more accurately mimic the current gopls execution mode, where gopls
is run as a sidecar and communicated with via a pipe.
Updates golang/go#36879
Change-Id: I0e14ed0e628333ba2cc7b088009f1887fcaa82a5
Reviewed-on: https://go-review.googlesource.com/c/tools/+/218777
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>