Move to header only dependency on libnativehelper

Use same approach for CompatabilityCloseMonitor for android and when
unbundled.

Rename unbundled libnativehelper includes to match names of
libnativehelper header only includes.

Move Netfd.h from libcore to conscrypt.

Run affected headers through clang-format for repo-hooks.

Bug: 119840313
Test: m -j100 checkbuild
Change-Id: I7ca3137ad7d45db34d97b25566e7e84f2dddf337