feat(benchmarks): add plan diagnostics to SQL benchmark runners

[Omega359]

Which issue does this PR close?

• Part of [EPIC] Add SQL based benchmarking #21706.

Rationale for this change

The native sort-pushdown benchmark can print query plans and execution metrics, but SQL benchmarks do not provide equivalent diagnostics. Preserve that capability in the shared SQL harness before migrating the sort-pushdown benchmarks.

What changes are included in this PR?

• Use the existing --debug / DEBUG option to print logical, optimized logical, physical, and post-execution metric plans for SQL benchmark run queries.
• Support both the simple and Criterion runners, including buffered execution used for result persistence and validation.
• Retain the executed physical plan so the reported metrics come from that execution. Buffered execution reuses the same plan for validation and collection.

What is the testing strategy for this PR?

A test as written to cover the new diagnostic information. A sample of benchmarks were run with and without the diagnostics to verify they worked.

Are there any user-facing changes?

SQL benchmarks now emit plan diagnostics when --debug or DEBUG=true is enabled. Diagnostics are disabled by default. As with the native benchmark, diagnostic output occurs during execution and affects measured timings.

[alamb]

Thanks!

[alamb]

I merged up from main -- the Ci failure seems unrelated to this change