internal: increase timeout non timeout test in xds/client/v2 (#4006)

xds/internal/client/v2/client_test.go

diff --git a/xds/internal/client/v2/client_test.go b/xds/internal/client/v2/client_test.go
index 7b8d678..5c9fbd5 100644
--- a/xds/internal/client/v2/client_test.go
+++ b/xds/internal/client/v2/client_test.go
@@ -609,10 +609,8 @@
 	fakeServer.XDSResponseChan <- &fakeserver.Response{Err: errors.New("RPC error")}
 	t.Log("Bad LDS response pushed to fakeServer...")
 
-	sCtx, sCancel := context.WithTimeout(context.Background(), defaultTestShortTimeout)
-	defer sCancel()
-	val, err := fakeServer.XDSRequestChan.Receive(sCtx)
-	if err == context.DeadlineExceeded {
+	val, err := fakeServer.XDSRequestChan.Receive(ctx)
+	if err != nil {
 		t.Fatalf("Timeout expired when expecting LDS update")
 	}
 	gotRequest := val.(*fakeserver.Request)