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GH-37144: [C++] Add RecordBatchFileReader::To{RecordBatches,Table} (#37167)

### Rationale for this change

`RecordBatchReader` has them but `RecordBatchFileReader` doesn't. They are convenient.

### What changes are included in this PR?

Add them.

### Are these changes tested?

Yes.

### Are there any user-facing changes?

Yes.
* Closes: #37144

Authored-by: Sutou Kouhei <kou@clear-code.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>