[FAB-12209] Speedup TestShuffle in discovery

The test TestShuffle uses a slice of 1 million elements in order the
shuffling to fail with a negligible probability.

This runs in 2 seconds without race detector, but -
with race detector enabled it runs very very slow (20 seconds).

I changed the million to a thousand, and the number of
permutations should be still high enough to have the test
fail with low probability.

FAB-12209 #done

Change-Id: I57ccfbe0051055bb470f1c87d44eb813ecd6196e
Signed-off-by: yacovm <yacovm@il.ibm.com>

Author: yacovm

discovery/client/client_test.go

@@ -555,7 +555,7 @@ func TestClient(t *testing.T) {
 				used[name] = struct{}{}
 			}
 		}
-		fmt.Printf("Used peers: %#v\n", used)
+		t.Logf("Used peers: %#v\n", used)
 		assert.Equalf(t, len(acceptablePeers), len(used), "expecting each endorser to be returned at least once")
 	})
 }

discovery/client/selection_test.go

@@ -15,7 +15,7 @@ import (
 )
 
 func TestShuffle(t *testing.T) {
-	endorsers := make(Endorsers, 1000000)
+	endorsers := make(Endorsers, 1000)
 	for i := 0; i < len(endorsers); i++ {
 		endorsers[i] = &Peer{
 			StateInfoMessage: stateInfoWithHeight(uint64(i)),