Odd `/` and `//` paths in JDBC optimized location overlap checks

Based on: https://github.com/apache/polaris/pull/5003#discussion_r3552655603

`persistence/relational-jdbc/.../QueryGenerator` uses paths like `/` and `//` in location overlap checks on S3 locations (as an example)

These paths do not look correct when they are derived from the URI host separator, e.g. `s3://bucket/path`

Start by reading persistence/relational-jdbc/.../QueryGenerator, focusing on the location overlap checks and how URI host separators produce paths for locations such as s3://bucket/path. Trace the generated values for / and //, then verify that the overlap checks use the intended location paths without extra separators.

Written by the indexing model from the issue text.