Sort the server list before iterate to keep consistent between workers

[sighingnow]

What do these changes do?

In some cases the server list is in different order inside different process, and yields unexpected partition dispatch plan, e.g.,

worker 1:

2023-06-30 04:55:27.508318003 INFO  (src/bin/gaia_executor.rs:167) [main] partition_lists before dedup = {1: [0, 1, 2, 3], 0: [0, 1, 2, 3]}
2023-06-30 04:55:27.508339604 INFO  (src/bin/gaia_executor.rs:177) [main] partition_lists = {1: [2, 3], 0: [0, 1]}
2023-06-30 04:55:27.508355604 INFO  (src/bin/gaia_executor.rs:190) [main] partition_server_index_map = {0: 0, 2: 1, 3: 1, 1: 0}
2023-06-30 04:55:27.508361404 INFO  (src/bin/gaia_executor.rs:105) [main] server_index: 0, partition_server_index_map: {0: 0, 2: 1, 3: 1, 1: 0}
2023-06-30 04:55:27.508449905 INFO  (/work/interactive_engine/executor/engine/pegasus/server/src/rpc.rs:314) [main] starting RPC job server on 0.0.0.0:8257 ...
2023-06-30 04:55:27.508457305 INFO  (src/bin/gaia_executor.rs:198) [main] RPC server of server[0] start on 0.0.0.0:8257

worker 2:

2023-06-30 04:55:27.508489205 INFO  (src/bin/gaia_executor.rs:167) [main] partition_lists before dedup = {0: [0, 1, 2, 3], 1: [0, 1, 2, 3]}
2023-06-30 04:55:27.508507605 INFO  (src/bin/gaia_executor.rs:177) [main] partition_lists = {0: [2, 3], 1: [0, 1]}
2023-06-30 04:55:27.508523506 INFO  (src/bin/gaia_executor.rs:190) [main] partition_server_index_map = {2: 0, 0: 1, 3: 0, 1: 1}
2023-06-30 04:55:27.508529206 INFO  (src/bin/gaia_executor.rs:105) [main] server_index: 1, partition_server_index_map: {2: 0, 0: 1, 3: 0, 1: 1}
2023-06-30 04:55:27.508591606 INFO  (/work/interactive_engine/executor/engine/pegasus/server/src/rpc.rs:314) [main] starting RPC job server on 0.0.0.0:8259 ...
2023-06-30 04:55:27.508598706 INFO  (src/bin/gaia_executor.rs:198) [main] RPC server of server[1] start on 0.0.0.0:8259

Related issue number

Fixes #2675