Disable lint checks which do not apply in the platform

Lint is primarily targeted at Android app developers, and some of the
checks reflect that. Some of these checks do not apply to the platform
code, where they can produce false positives.

This CL adds a number of these to an exclude list passed in to lint.
Also reenables a check previously disabled because of a bug which has
since been fixed, HardcodedDebugMode, and downgrades from error to
warning a few more lint checks which have existing violations in the
codebase when lint is upgraded to the latest version.

Test: Existing
Bug: None
Change-Id: Icbfbcfd51516c43c342e0d3cdb6973278110fd35