clustermd_tests: add test case to test switch-resync against cluster-raid10

03r10_switch-resync:
Create new array, 1 node is doing resync and other node would keep PENDING,
stop the array in resync node, other node would take it over and continue
to complete the resync.

Signed-off-by: Zhilong Liu <zlliu@suse.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>

clustermd_tests/03r10_switch-resync

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+mdadm -CR $md0 -l10 -b clustered --layout n2 -n2 $dev0 $dev1
+ssh $NODE2 mdadm -A $md0 $dev0 $dev1
+check $NODE1 resync
+check $NODE2 PENDING
+stop_md $NODE1 $md0
+check $NODE2 resync
+check $NODE2 wait
+mdadm -A $md0 $dev0 $dev1
+check all raid10
+check all bitmap
+check all nosync
+check all state UU
+check all dmesg
+stop_md all $md0
+
+exit 0