Add HandlerExecutor & BT to modules-utils

For Mainline Project, modules needs to depend on some specific files.
modules-utils regroup stand-alone library for such use.
This cl is adding
* BackgroundThread
* BackgroundThreadTest
* HandlerExecutor

Test has been refactored to be more futur-proof.

Bug: 198418216
Tag: #refactor
Test: atest ModulesUtilsTests
Change-Id: Ie82753719f22d03f1678e4b4e1c550b0dc050bd6
8 files changed
tree: 9a6ad115f8c516f389d7ebd9d1f50718711bfa3e
  1. build/
  2. java/
  3. javatests/
  4. tools/
  5. Android.bp
  6. OWNERS
  7. PREUPLOAD.cfg
  8. TEST_MAPPING