arrow

GH-38438: [C++] Dataset: Trying to fix the async bug in Parquet dataset (#38466)



### Rationale for this change

Origin mentioned https://github.com/apache/arrow/issues/38438

1. When PreBuffer is default enabled, the code in `RowGroupGenerator::FetchNext` would switch to async mode. This make the state handling more complex
2. In `RowGroupGenerator::FetchNext`, `[this]` is captured without `shared_from_this`. This is not bad, however, `this->executor_` may point to a invalid address if this dtor.

This patch also fixes a lifetime issue I founded in CSV handling.

### What changes are included in this PR?

1. Fix handling in `cpp/src/parquet/arrow/reader.cc` as I talked above
2. Fix a lifetime problem in CSV

### Are these changes tested?

I test it locality. But don't know how to write unittest here. Fell free to help.

### Are there any user-facing changes?

Bugfix

* Closes: #38438

Authored-by: mwish <maplewish117@gmail.com>
Signed-off-by: Benjamin Kietzman <bengilgit@gmail.com>