arrow

GH-37102: [Go][Parquet] Encoding: Make BitWriter Reserve when ReserveBytes (#37112)



### Rationale for this change

See https://github.com/apache/arrow/issues/37102. Also fixes #35718

Golang BitWriter didn't reserve when `ReserveBytes` called. So it make it wrong.

### What changes are included in this PR?

Change `ReserveBytes` impl

### Are these changes tested?

Currently not

### Are there any user-facing changes?

bugfix

* Closes: #37102

Lead-authored-by: Matt Topol <zotthewizard@gmail.com>
Co-authored-by: mwish <maplewish117@gmail.com>
Signed-off-by: Matt Topol <zotthewizard@gmail.com>