Hi!
I have a problem with ARRAY_CONCAT operator.
The following code failed with the exception ''No match found for function
signature array_concat(<INTEGER ARRAY>, <INTEGER ARRAY>)".
```
val config = Frameworks.newConfigBuilder()
.parserConfig(parserConfig)
.defaultSchema(CalciteSchema.createRootSchema(false, false).plus())
.operatorTable(SqlOperatorTables.chain(
SqlStdOperatorTable.instance(),
SqlLibraryOperatorTableFactory.INSTANCE.getOperatorTable(
SqlLibrary.BIG_QUERY
)))
.programs(Programs.standard())
.build()
val planner = Frameworks.getPlanner(config)
val query = "SELECT ARRAY_CONCAT(ARRAY[1, 2], ARRAY[2, 3])"
val parsedSqlNode = planner.parse(query)
planner.validate(parsedSqlNode)
```
Am I doing something wrong or it is a bug?
