Resolve cross-schema complex column types by schema ID

[skhe]

Summary

• Resolve complex column types using the server's type schema ID, rather than the result table's schema or the login user.
• Add a real DM regression with identically named types in two schemas, including a local table that references a foreign VARRAY of objects containing DECIMAL(30,8) and Unicode text.

Verification

• GB18030 real database: 192 passed, 6 deselected.
• UTF8 real database: 187 passed, 5 skipped (local instance lacks admin password), 6 deselected.
• Vendored Go driver: go test ./... passed.
• git diff --check and Go formatting passed.