devcontainer, would like to setup a devcontainer

 for integration testing to be more deterministic.

golang/go#12868 (comment)

One code change that i think is overall safe.

.devcontainer/devcontainer.json

@@ -0,0 +1,11 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/go
+{
+	"name": "Go",
+	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+	"image": "mcr.microsoft.com/devcontainers/go:0-1-bullseye",
+	"features": {
+		"ghcr.io/devcontainers/features/java:1": {
+		}
+	}
+}

server_java_test.go

@@ -67,7 +67,7 @@ func (srv *server) Start() error {
 	srv.cmd = exec.CommandContext(ctx, srv.cmdString, srv.cmdArgs...)
 	srv.cmd.Stdout = srv.stdout
 	srv.cmd.Stderr = srv.stderr
-	srv.cmd.Env = srv.cmdEnv
+	srv.cmd.Env = append(os.Environ(), srv.cmdEnv...)
 
 	return srv.cmd.Start()
 }