Fix PostgreSQL routine reader for functions with unnamed parameters

[DavidBoone]

Reading the schema of any PostgreSQL database containing a user function with a mix of named and unnamed parameters aborts the entire read with A parameter name is required. Call WithName before Build. from ParameterBuilder.Build(). One such function anywhere in the database kills the whole read; the only caller workaround is turning routine reading off.

pg_proc.proargnames is NULL only when a function has no named parameters at all. As soon as any parameter is named — which PostgreSQL forces for every function with an OUT parameter or a RETURNS TABLE clause — unnamed inputs come back as empty strings, so they passed the parameter_name IS NOT NULL filter and reached the builder nameless.

create function demo.f(int, out result text) language sql as $$ select 'x' $$;
create function demo.g(int) returns table (id int) language sql as $$ select 1 $$;

The filter is dropped and unnamed arguments are named positionally as $n, matching PostgreSQL's own naming. Dropping them instead would silently corrupt the parameter list, so they are kept.

First commit adds the repro functions to the test scripts — every PostgreSQL schema reader test fails at that commit. Second commit has the reader fix plus tests asserting the $n naming. Full PostgreSQL test suite passes on the branch.