Move BitUtils, RingBuffer test to coretests

The utilities are part of com.android.internal.util, but were
historically tested as part of the services.net tests. They were then
mistakenly moved to packages/modules/Connectivity with the rest of the
networking code, but actually belong in coretests.

Bug: 187935317
Test: atest FrameworksCoreTests
Change-Id: I74702f6a4d9bed5985d2a830dacd78129a7854a8
2 files changed