LOOKUP not supported in v2 engine

This may be an intentional choice but LOOKUP (dimension table use) does not appear to work in v2 engine. Repro steps are:

- write any query using LOOKUP in v1 engine, validate that it works
- issue the same query to the v2 engine
- note that it fails with a message like:
```
Caused by: org.apache.calcite.runtime.CalciteContextException: From line 2, column 63 to line 2, column 126: No match found for function signature LOOKUP(, , , )
at jdk.internal.reflect.GeneratedConstructorAccessor219.newInstance(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
at org.apache.calcite.runtime.Resources$ExInstWithCause.ex(Resources.java:505)
...
Caused by: org.apache.calcite.sql.validate.SqlValidatorException: No match found for function signature LOOKUP(, , , )
at jdk.internal.reflect.GeneratedConstructorAccessor218.newInstance(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
at org.apache.calcite.runtime.Resources$ExInstWithCause.ex(Resources.java:505))
```