Fixes #2636

PR improves logic of sample by factory selection .
It doesn't allow using SampleByFirstLastRecordCursorFactory when column list contains anything other than :

• first/last aggregates
• designated timestamp column
• filtered symbol column

It also enables order by geohash columns .

In master branch SQL such as :

CREATE TABLE pos (
  id int
  geo GEOHASH(5b)
);
insert into pos  values ( 1,##00001), ( 2,##00010), ( 3, ##00011 ), ( 16, ##10000 );
select * from pos order by geo desc;

triggers:

java.lang.UnsupportedOperationException at io.questdb.griffin.engine.functions.AbstractGeoHashFunction.getSymbolB(AbstractGeoHashFunction.java:154) at io.questdb.cairo.sql.VirtualRecord.getSymB(VirtualRecord.java:198) at io.questdb.griffin.engine.orderby.LongTreeChain.put(LongTreeChain.java:75) at io.questdb.griffin.engine.orderby.SortedLightRecordCursor.buildChain(SortedLightRecordCursor.java:130) at io.questdb.griffin.engine.orderby.SortedLightRecordCursor.hasNext(SortedLightRecordCursor.java:79) at io.questdb.cutlass.http.processors.JsonQueryProcessorState.onQuerySetupFirstRecord(JsonQueryProcessorState.java:755) at io.questdb.cutlass.http.processors.JsonQueryProcessorState.doFirstRecordLoop(JsonQueryProcessorState.java:463) at io.questdb.cutlass.http.processors.JsonQueryProcessorState.onQueryPrefix(JsonQueryProcessorState.java:719) at io.questdb.cutlass.http.processors.JsonQueryProcessorState.resume(JsonQueryProcessorState.java:864) at io.questdb.cutlass.http.processors.JsonQueryProcessor.doResumeSend(JsonQueryProcessor.java:306) at io.questdb.cutlass.http.processors.JsonQueryProcessor.executeSelect(JsonQueryProcessor.java:550) at io.questdb.cutlass.http.processors.JsonQueryProcessor.executeNewSelect(JsonQueryProcessor.java:534) at io.questdb.cutlass.http.processors.JsonQueryProcessor.compileQuery(JsonQueryProcessor.java:423) at io.questdb.cutlass.http.processors.JsonQueryProcessor.execute0(JsonQueryProcessor.java:186) at io.questdb.cutlass.http.processors.JsonQueryProcessor.onRequestComplete(JsonQueryProcessor.java:236) at io.questdb.cutlass.http.HttpConnectionContext.handleClientRecv(HttpConnectionContext.java:600) at io.questdb.cutlass.http.HttpConnectionContext.handleClientOperation(HttpConnectionContext.java:203) at io.questdb.cutlass.http.HttpServer$1.lambda$$0(HttpServer.java:86) at io.questdb.network.AbstractIODispatcher.processIOQueue(AbstractIODispatcher.java:178) at io.questdb.cutlass.http.HttpServer$1.run(HttpServer.java:101) at io.questdb.mp.Worker.run(Worker.java:118)

because comparator uses default (symbol) type .