[qa] Sort scripts by time for pull_tester and don't overwrite setup_chain

qa/pull-tester/rpc-tests.py

@@ -110,6 +110,8 @@ testScripts = [
     'receivedby.py',
     'mempool_resurrect_test.py',
     'txn_doublespend.py --mineblock',
+    'p2p-segwit.py',
+    'segwit.py',
     'txn_clone.py',
     'getchaintips.py',
     'rawtransactions.py',
@@ -131,13 +133,12 @@ testScripts = [
     'disablewallet.py',
     'sendheaders.py',
     'keypool.py',
+    'p2p-mempool.py',
     'prioritise_transaction.py',
     'invalidblockrequest.py',
     'invalidtxrequest.py',
     'abandonconflict.py',
     'p2p-versionbits-warning.py',
-    'p2p-segwit.py',
-    'segwit.py',
     'importprunedfunds.py',
     'signmessages.py',
 ]