SQLAlchemy compliance: restore binary type coverage

[laughingman7743]

Context

Parent issue: #736

BinaryTest is deleted even though Athena supports VARBINARY.
The remaining gap may involve bind encoding, literal rendering, reflection, or DBAPI result conversion.

Scope

• Run the SQLAlchemy binary compliance tests against Athena engine v3.
• Fix binary bind, literal, reflection, or result conversion behavior that belongs in the dialect.
• Re-enable supported binary tests.
• Gate only engine limitations that cannot be addressed by the dialect.

Acceptance criteria

• Supported BinaryTest nodes pass against Athena.
• Unit tests cover converter or compiler changes without AWS where possible.
• Existing bytes and VARBINARY behavior remains backward compatible.
• just lint passes.
• Athena tests are limited to binary nodes and run with -n 1.