logging: always enable DCHECK for the static analyzer

This helps us have less false-positives.

We do this instead of `#undef NDEBUG`, since undefing NDEBUG actually
gave us more false-positives (...and build breakages) than simply
leaving it defined.

Bug: None
Test: Ran the static analyzer across internal master. 213 fewer warnings
(15 Medium, 2 Low, the remainder are 'Analyzer'). All of the dropped
warnings I audited were false-positives. It adds ~3 Tidy warnings.
Change-Id: Ibedab60ca7e9d2b0772896222b83d2e7ab064afe