dap: ensure test client is closed on cleanup

The dap test wasn't waiting for the client's goroutines to complete
before exiting which caused a race condition that could cause it to log
to the dead test logger. This became apparent when `--count` of greater
than one was used since it caused the test to run long enough to trigger
the behavior. It would have also triggered if we had added more tests.

Add the client close to the cleanup so it waits for the goroutine to
finish before the test exits as it was properly supposed to do.

Signed-off-by: Jonathan A. Sternberg <jonathan.sternberg@docker.com>

dap/adapter_test.go

@@ -14,8 +14,6 @@ import (
 )
 
 func TestLaunch(t *testing.T) {
-	t.Skip("test fails with errgroup v0.16.0, that doesn't swallow panic in goroutine")
-
 	adapter, conn, client := NewTestAdapter[common.Config](t)
 
 	ctx, cancel := context.WithTimeoutCause(context.Background(), 10*time.Second, context.DeadlineExceeded)
@@ -83,14 +81,14 @@ func NewTestAdapter[C LaunchConfig](t *testing.T) (*Adapter[C], Conn, *Client) {
 	})
 
 	clientConn := logConn(t, "client", NewConn(rd2, wr1))
-	t.Cleanup(func() {
-		clientConn.Close()
-	})
+	t.Cleanup(func() { clientConn.Close() })
 
 	adapter := New[C]()
 	t.Cleanup(func() { adapter.Stop() })
 
 	client := NewClient(clientConn)
+	t.Cleanup(func() { client.Close() })
+
 	return adapter, srvConn, client
 }