Remove zlib divergence

Removed the zlib divergence where we had to replace line like
`#include "third_party/zlib/zlib.h"` with `#include <zlib.h>`. This was
done by creating an actual header file whose path is `third_party/zlib
zlib.h` that will include AOSP's header.

Test: m cronet_aml_net_net && atest net_unittests_tester
Bug: 321680067
Bug: 304217500
Change-Id: Ie794ff71c0d5f9c9083024bb5a3e05f1fadf6171
22 files changed