TBR nacl/channel/race: Fix race in channel test
TBR nacl/channel/race: Fix race in channel test

Handlers for a type were registered multiple times unintentionally and the order of registration changed the result

Change-Id: I9acf387551da6f5b0def7827af2b05d8091fcf3c

vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref