Unexpected ClassCastException with null query

[YuanchengJiang]

Describe the bug

java.lang.ClassCastException: class io.questdb.griffin.engine.functions.constants.NullConstant cannot be cast to class io.questdb.griffin.engine.functions.SymbolFunction (io.questdb.griffin.engine.functions.constants.NullConstant and io.questdb.griffin.engine.functions.SymbolFunction are in module io.questdb@7.1.1 of loader 'app')
	at io.questdb.griffin.engine.functions.bool.InSymbolCursorFunctionFactory.newInstance(InSymbolCursorFunctionFactory.java:54)
	at io.questdb.griffin.FunctionParser.checkAndCreateFunction(FunctionParser.java:386)
	at io.questdb.griffin.FunctionParser.createFunction(FunctionParser.java:780)
	at io.questdb.griffin.FunctionParser.visit(FunctionParser.java:311)
	at io.questdb.griffin.PostOrderTreeTraversalAlgo.traverse(PostOrderTreeTraversalAlgo.java:86)
	at io.questdb.griffin.FunctionParser.parseFunction(FunctionParser.java:239)
	at io.questdb.griffin.SqlCodeGenerator.generateSelectVirtualWithSubQuery(SqlCodeGenerator.java:3387)
	at io.questdb.griffin.SqlCodeGenerator.generateSelectVirtual(SqlCodeGenerator.java:3359)
	at io.questdb.griffin.SqlCodeGenerator.generateSelect(SqlCodeGenerator.java:2667)
	at io.questdb.griffin.SqlCodeGenerator.generateQuery0(SqlCodeGenerator.java:2272)
	at io.questdb.griffin.SqlCodeGenerator.generateQuery(SqlCodeGenerator.java:2259)
	at io.questdb.griffin.SqlCodeGenerator.generate(SqlCodeGenerator.java:186)
	at io.questdb.griffin.SqlCompiler.generate(SqlCompiler.java:2731)
	at io.questdb.griffin.SqlCompiler.compileUsingModel(SqlCompiler.java:1322)
	at io.questdb.griffin.SqlCompiler.compileInner(SqlCompiler.java:1271)
	at io.questdb.griffin.SqlCompiler.compileBatch(SqlCompiler.java:322)
	at io.questdb.cutlass.pgwire.PGConnectionContext.processQuery(PGConnectionContext.java:2413)
	at io.questdb.cutlass.pgwire.PGConnectionContext.parse(PGConnectionContext.java:1683)
	at io.questdb.cutlass.pgwire.PGConnectionContext.handleClientOperation(PGConnectionContext.java:418)
	at io.questdb.cutlass.pgwire.PGJobContext.handleClientOperation(PGJobContext.java:89)
	at io.questdb.cutlass.pgwire.PGWireServer$1.lambda$$0(PGWireServer.java:91)
	at io.questdb.network.AbstractIODispatcher.processIOQueue(AbstractIODispatcher.java:189)
	at io.questdb.cutlass.pgwire.PGWireServer$1.run(PGWireServer.java:128)
	at io.questdb.mp.Worker.run(Worker.java:118)

This bug could be similar to #3356. As they gave different exceptions, I create two issues.

To reproduce

select null in null;

Expected Behavior

No response

Environment

- **QuestDB version**: 7.1.1
- **OS**: ubuntu 20.04

Additional context

No response