list_free in addRangeTableEntryForJoin

Hi Hackers

I have identified a potential memory leak in the
`addRangeTableEntryForJoin()` function. The second parameter of
`addRangeTableEntryForJoin()`, `colnames`, is a `List*` that is
concatenated with another `List*`, `eref->colnames`, using
`list_concat()`. We need to pass only the last `numaliases` elements of
the list, for which we use `list_copy_tail`. This function creates a
copy of the `colnames` list, resulting in `colnames` pointing to the
current list that will not be freed. Consequently, a new list is already
concatenated.

To address this issue, I have invoked `list_free(colnames)` afterwards.
If anyone is aware of where the list is being freed or has any
suggestions for improvement, I would greatly appreciate your input.

Best Regards,

Ilia Evdokimov,

TantorLabs LCC