[BUG] Fix routine load task is aborted, throw NullPointerException

[xinyiZzz]

Describe the bug
Routine load import task, if there is where_predicates, in expr rewrite, NullPointerException may be reported when extracting common factors, for example

CREATE ROUTINE LOAD load_name ON test COLUMNS (k1, k2, k3, k4, k5, k6, k10, k11, k7, k8, k9),WHERE k1 between 10 and 13 or k2 is null or lower(k7) regexp".*04$" or k10 > "2019-01-01" or k11 > "2019-01-01" FROM KAFKA (……);

Error:

java.lang.NullPointerException: null
	at org.apache.doris.rewrite.ExtractCommonFactorsRule.extractCommonFactors(ExtractCommonFactorsRule.java:151) ~[palo-fe.jar:3.4.0]
	at org.apache.doris.rewrite.ExtractCommonFactorsRule.apply(ExtractCommonFactorsRule.java:68) ~[palo-fe.jar:3.4.0]
	at org.apache.doris.rewrite.ExprRewriter.applyRuleOnce(ExprRewriter.java:82) ~[palo-fe.jar:3.4.0]
	at org.apache.doris.rewrite.ExprRewriter.rewrite(ExprRewriter.java:76) ~[palo-fe.jar:3.4.0]
	at org.apache.doris.planner.LoadScanNode.initWhereExpr(LoadScanNode.java:85) ~[palo-fe.jar:3.4.0]
	at org.apache.doris.planner.LoadScanNode.initAndSetWhereExpr(LoadScanNode.java:60) ~[palo-fe.jar:3.4.0]
	at org.apache.doris.planner.StreamLoadScanNode.init(StreamLoadScanNode.java:144) ~[palo-fe.jar:3.4.0]
	at org.apache.doris.planner.StreamLoadPlanner.plan(StreamLoadPlanner.java:139) ~[palo-fe.jar:3.4.0]
	at org.apache.doris.load.routineload.RoutineLoadJob.plan(RoutineLoadJob.java:815) ~[palo-fe.jar:3.4.0]
	at org.apache.doris.load.routineload.KafkaTaskInfo.rePlan(KafkaTaskInfo.java:116) ~[palo-fe.jar:3.4.0]
	at org.apache.doris.load.routineload.KafkaTaskInfo.createRoutineLoadTask(KafkaTaskInfo.java:95) ~[palo-fe.jar:3.4.0]
	at org.apache.doris.load.routineload.RoutineLoadTaskScheduler.scheduleOneTask(RoutineLoadTaskScheduler.java:174) ~[palo-fe.jar:3.4.0]
	at org.apache.doris.load.routineload.RoutineLoadTaskScheduler.process(RoutineLoadTaskScheduler.java:108) [palo-fe.jar:3.4.0]
	at org.apache.doris.load.routineload.RoutineLoadTaskScheduler.runAfterCatalogReady(RoutineLoadTaskScheduler.java:83) [palo-fe.jar:3.4.0]
	at org.apache.doris.common.util.MasterDaemon.runOneCycle(MasterDaemon.java:58) [palo-fe.jar:3.4.0]
	at org.apache.doris.common.util.Daemon.run(Daemon.java:116) [palo-fe.jar:3.4.0]