resolv: First pass of un-ifdef

Removed #ifdefs for symbols which are always defined (ANDROID_CHANGES)
and symbols which are never defined (COMPAT__RES, _LIBRESOLV, sun,
ultrix, lint).

Leaving in DEBUG for now because we might want to toggle it in the
future. It's currently defined on a module-by-module basis.

Test: atest netd_integration_test
Change-Id: Iaeaf096266e6ed10895a16253c5f1bdb05760dce
10 files changed