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GH-38751: [C++][Go][Parquet] Add tests for reading Float16 files in parquet-testing (#38753)



### Rationale for this change

Validates compatibility between implementations when reading `Float16` columns.

### What changes are included in this PR?

- Bumps `parquet-testing` commit to latest to use the recently-added files
- Adds reader tests for C++ and Go in the same vein as https://github.com/apache/arrow-rs/pull/5003

### Are these changes tested?

Yes

### Are there any user-facing changes?

No

* Closes: #38751

Authored-by: benibus <bpharks@gmx.com>
Signed-off-by: Matt Topol <zotthewizard@gmail.com>