Remove legacy dexopt code from Package Manager.

This is the first CL, which only removes large chunks of dead code. More
granular cleanup cleanup will be handled in subsequent CLs.

Bug: 258223472
Bug: 6527146
Test: atest FrameworksServicesTests FrameworksMockingServicesTests
Test: Presubmit
Flag: EXEMPT cleanup
Change-Id: I47cf86bf9519d0d0c10ba2c10796b1c35466ac06