remove sleep that guarded against nondeterministic behavior

internal/evidence/reactor_test.go

@@ -435,11 +435,6 @@ func TestReactorBroadcastEvidence_Committed(t *testing.T) {
 	// start the network and ensure it's configured
 	rts.start(t)
 
-	// without the following sleep the test consistently fails;
-	// likely because the sleep forces a context switch that lets
-	// the router process other operations.
-	time.Sleep(2 * time.Millisecond)
-
 	// The secondary reactor should have received all the evidence ignoring the
 	// already committed evidence.
 	rts.waitForEvidence(t, evList[numEvidence/2:], secondary.NodeID)