arrow

ARROW-4520: [C++] use voidified expr to ignore DCHECK() custom messages in NDEBUG

For release builds `DCHECK( x ) << y << z;` currently expands to

```
((void)(x));
while (false) ::arrow::util::ArrowLogBase() << y << z;
```

This is unreachable which is an error using clang-7

Author: Benjamin Kietzman <bengilgit@gmail.com>

Closes #3599 from bkietz/ARROW-4520-ignore-custom-messages-for-release-builds and squashes the following commits:

e508537e <Benjamin Kietzman> use Antoine's suggestion
580498d5 <Benjamin Kietzman> Revert "rewriting DCHECK_OK to guarantee evaluation"
63ee8497 <Benjamin Kietzman> Revert "rewriting DCHECK(expr.ok()) to DCHECK_OK(expr)"
265a36db <Benjamin Kietzman> rewriting DCHECK(expr.ok()) to DCHECK_OK(expr)
8d7b5a1b <Benjamin Kietzman> rewriting DCHECK_OK to guarantee evaluation
dd763037 <Benjamin Kietzman> Revert "remove side effects from DCHECK conditions"
87a58eec <Benjamin Kietzman> remove side effects from DCHECK conditions
ca2cdb30 <Benjamin Kietzman> Revert "use Antoine's suggestion"
aacbd761 <Benjamin Kietzman> use Antoine's suggestion
99cf3284 <Benjamin Kietzman> don't reference undefined macros
d86e114f <Benjamin Kietzman> use voidified log expr for NDEBUG DCHECKs
bc43abe5 <Benjamin Kietzman> add ArrowLogIgnore and use for release mode DCHECK*