Unable to get tables and db version from Comdb2MetaData sequentially

[jeffrytyn]

Describe the bug
When querying the database for all available tables through the Comdb2MetaData object in cdb2jdbc, if the database version is also queried, it breaks and is unable to find the tables after. Not sure if this is intended behavior

To Reproduce
Here is an example test case that reproduces the issue
https://gist.github.com/jeffrytyn/50403cb3b74dcdb8457aa537d771b6e0

Expected behavior
I expect the test to pass but it fails

Additional context
Looking inside the Comdb2MetaData class, it has instance variables ps and stmt.
ps is creating inside getTables method from the conn object
stmt is created in the constructor of the class using the same conn object
This conn object itself has an instance variable hndl

The ResultSet tables is the output of ps.executeQuery, where ps is a Comdb2PreparedStatement created with hndl.
version is the output of stmt.executeQuery, where stmt is a Comdb2Statement created with hndl also

tables.next() invokes hndl.next(), but because the same hndl was used to get the version, it now returns false instead of true. Seems like different hndls should be used

[riverszhang89]

Multiple resultsets on a single connection are supported. You'd read the resultset of the 1st query first, and then make the 2nd query.