Data channel test race fixes
commit 4aa49adb
webrtc: fix an off-by-one calculating low-threshold
We were not signalling low-threshold when the previous amount was at
exactly the low-threshold mark.
commit 47991e36
webrtc: fix a slightly racy test
There is no guarantee that the peer data channel has transitioned to
open when we do.
commit 3839b442
webrtc: remove debugging leftover