Ruogu Du

Results 3 issues of Ruogu Du

`src/planner/abstract_scan_plan.cpp: 53` Fixed in #1281 https://github.com/cmu-db/peloton/blob/78b85dc21d5f1d7b09b150380ecec22b92ea804e/src/planner/abstract_scan_plan.cpp#L53

`trigger_test.cpp: 153` assumes the LIFO order in table's trigger list. But I think the order could not be guaranteed. #1281

https://github.com/oltpbenchmark/oltpbench/blob/b61f29da1c16ed829c0dbeee66498adb07692a3c/config/sample_pgtpcc_config.xml#L43 There should be only 5 weights.