Rework general-tests optimization

Rework general-tests optimization to use the test discovery agent to
determine the modules that are needed to be included in
general-tests.zip. Also start reporting optimization decisions silently.

Test: atest build_test_suites_test; atest optimized_targets_test
Bug: 358215235
Change-Id: Iabff6729e5743805167eed87d7ef5d901b255a61