cmd/gogio: don't hang on some e2e test errors

For example, if the test app fails to start on wayland, we'd block
~forever (ten minutes) waiting for it to render its first frame.

We don't have a good solution right now. But at least we can use a
relatively short timeout, to help out the human who rightfully expects
a result within ten seconds.

While at it, remove a sway "get_seats" command, which was a leftover
from my debugging of what input devices are available when running
headless.

Signed-off-by: Daniel Martí <mvdan@mvdan.cc>

cmd/gogio/js_test.go

@@ -129,7 +129,7 @@ func (d *JSTestDriver) Start(t_ *testing.T, path string, width, height int) {
 	}
 
 	// Wait for the gio app to render.
-	<-d.frameNotifs
+	waitForFrame(d.t, d.frameNotifs)
 }
 
 func (d *JSTestDriver) Screenshot() image.Image {
@@ -154,5 +154,5 @@ func (d *JSTestDriver) Click(x, y int) {
 	}
 
 	// Wait for the gio app to render after this click.
-	<-d.frameNotifs
+	waitForFrame(d.t, d.frameNotifs)
 }