scripted-diff: use self.sync_* methods

-BEGIN VERIFY SCRIPT-
sed -i -e 's/sync_blocks(self.nodes)/self.sync_blocks()/g'     $(git grep -l 'sync_blocks(self.nodes)'   ./test/functional/*.py)
sed -i -e 's/sync_mempools(self.nodes)/self.sync_mempools()/g' $(git grep -l 'sync_mempools(self.nodes)' ./test/functional/*.py)

sed -i -e 's/  sync_blocks(/  self.sync_blocks(/g'     $(git grep -l sync_blocks   ./test/functional/*.py)
sed -i -e 's/  sync_mempools(/  self.sync_mempools(/g' $(git grep -l sync_mempools ./test/functional/*.py)
-END VERIFY SCRIPT-

test/functional/wallet_keypool_topup.py

@@ -67,7 +67,7 @@ class KeypoolRestoreTest(BitcoinTestFramework):
             self.nodes[0].generate(1)
             self.nodes[0].sendtoaddress(addr_extpool, 5)
             self.nodes[0].generate(1)
-            sync_blocks(self.nodes)
+            self.sync_blocks()
 
             self.log.info("Restart node with wallet backup")
             self.stop_node(idx)