Split distributed/version_compat.h into dependency-free
pg_version_compat.h, and the original which still has
dependencies. The original doesn't have much purpose, but until other
files have better discipline about including the correct header files,
then it's still needed.
Also make distributed/listutils.h dependency-free. Should be moved
outside of 'distributed' subdirectory, but that will cause significant
code churn, so leave for another cleanup patch.
Now both files can be included in columnar without creating a
dependency on citus.
Postgres changed stats expression types as of PG14. Hence we needed to
write the AppendColumnNames method. Also they removed the error on PG
side so we remove it as well.
Relevant commits on pg14:
a4d75c86bf15220df22de0a92c819ecef9db3849
388e75ad33489b77cfb9a8590a91e9287d8fb960