MINOR: Enable multi-statement benchmark queries

[andygrove]

Which issue does this PR close?

N/A

Rationale for this change

q15.sql contains two SQL statements and this was not supported by the benchmark runner

What changes are included in this PR?

Support multiple queries per file

Are there any user-facing changes?

No

[matthewmturner]

When running Q15 do we get a new error now? Something like CREATE VIEW isnt implemented?

[matthewmturner]

If we get this merged first i can enable Q15 in #2279

[yjshen]

LGTM.

An off-topic question: I've noticed there were instructions on how to get golden files and get results verified but removed before. Do you think it's the time to add goldens and enable verify_query here for tpc-h?

Currently, these tests are skipped TPCH_DATA environment variable not set, skipping test

[andygrove]

When running Q15 do we get a new error now? Something like CREATE VIEW isnt implemented?

Yes, exactly that!

[andygrove]

LGTM.

An off-topic question: I've noticed there were instructions on how to get golden files and get results verified but removed before. Do you think it's the time to add goldens and enable verify_query here for tpc-h?

Currently, these tests are skipped TPCH_DATA environment variable not set, skipping test

The current approach is for developers to use the tpch toolkit to generate the expected answers locally and then set this env var to enable those tests. It would be nice if we could enable CI to do this as well.