internal/lsp/lsprpc: quiet the handshaker during regtests

There's a bunch of noise in regtest results related to the LSP forwarder
handshake.

lsprpc.StreamServer was already configurable to disable connection
logging in tests. Use this configuration to also disable handshake
logging.

Change-Id: I4b00e23d1f0bc6dc5fdd1f6f470f0b892c6791bc
Reviewed-on: https://go-review.googlesource.com/c/tools/+/249418
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>

internal/lsp/lsprpc/lsprpc.go

@@ -77,7 +77,7 @@ func (s *StreamServer) ServeStream(ctx context.Context, conn jsonrpc2.Conn) erro
 	ctx = protocol.WithClient(ctx, client)
 	conn.Go(ctx,
 		protocol.Handlers(
-			handshaker(session, executable,
+			handshaker(session, executable, s.logConnections,
 				protocol.ServerHandler(server,
 					jsonrpc2.MethodNotFound))))
 	if s.logConnections {
@@ -497,7 +497,7 @@ const (
 	sessionsMethod  = "gopls/sessions"
 )
 
-func handshaker(session *cache.Session, goplsPath string, handler jsonrpc2.Handler) jsonrpc2.Handler {
+func handshaker(session *cache.Session, goplsPath string, logHandshakes bool, handler jsonrpc2.Handler) jsonrpc2.Handler {
 	return func(ctx context.Context, reply jsonrpc2.Replier, r jsonrpc2.Request) error {
 		switch r.Method() {
 		case handshakeMethod:
@@ -506,11 +506,15 @@ func handshaker(session *cache.Session, goplsPath string, handler jsonrpc2.Handl
 			// client.
 			var req handshakeRequest
 			if err := json.Unmarshal(r.Params(), &req); err != nil {
-				log.Printf("Error processing handshake for session %s: %v", session.ID(), err)
+				if logHandshakes {
+					log.Printf("Error processing handshake for session %s: %v", session.ID(), err)
+				}
 				sendError(ctx, reply, err)
 				return nil
 			}
-			log.Printf("Session %s: got handshake. Logfile: %q, Debug addr: %q", session.ID(), req.Logfile, req.DebugAddr)
+			if logHandshakes {
+				log.Printf("Session %s: got handshake. Logfile: %q, Debug addr: %q", session.ID(), req.Logfile, req.DebugAddr)
+			}
 			event.Log(ctx, "Handshake session update",
 				cache.KeyUpdateSession.Of(session),
 				tag.DebugAddress.Of(req.DebugAddr),