GeezerVison

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Partitioned DML executed through the Cloud Spanner DB-API driver previously
failed whenever query parameters were used. The driver passed raw positional
placeholders and parameter lists directly to the database rather than converting
them into the named parameters and data types expected by Cloud Spanner.

Additionally, statement parsing historically mutated SQL statements in place
to automatically append a dummy "WHERE 1=1" clause to update and delete statements.
Injecting this dummy clause into Partitioned DML is dangerous because Partitioned
DML is non-atomic, irreversible, and cannot be rolled back. Bypassing Cloud
Spanner's requirement for an explicit WHERE clause risks unintended full-table
modifications.

This change addresses these issues by:
- Properly translating and passing query parameters and their data types
  during Partitioned DML execution.
- Making statement parsing pure and side-effect free so SQL statements are
  no longer mutated during classification.
- Ensuring Partitioned DML statements never receive an automatic dummy WHERE
  clause, keeping Cloud Spanner's safety checks intact.
- Guarding Partitioned DML mode so that statements executed inside an explicit
  transaction always run as atomic transactional DML.
- Retaining automatic dummy WHERE clause injection exclusively for transactional
  and batch DML to preserve full backwards compatibility for existing applications.

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