More `android.util` internals, with tests.

Internal test authors are likely going to want to use internal
utilities that aren't in the official API surface.  This change adds
those to Ravenwood, along with local tests to confirm they work.

Bug: 292141694
Test: atest-dev FrameworksUtilTestsRavenwood
Change-Id: I0f4df50416d153418d4525bd8ec5c4dbf04521a2