Elements in Empty List Resolving to STRING by Default Causes Issues

[mxwli]

If we write a query like this:

UNWIND $idList as tid MATCH (t:tag {id: tid}) RETURN t;

Where id expects an INT64 type, the query runs fine on a non empty $idList. However, when we have idList = [], then the query gives

Expression tid has data type STRING but expected INT64. Implicit cast is not supported.

[andyfengHKU]

Should be fixed in #3374