Move initZipPathValidator() into ActivityThread

This CL is just an internal cherry-pick of aosp/2428074 because of automerger conflicts.

initZipPathValidator() relies on CompatChanges#isChangeEnabled() to work
as intended, however, the current place, RuntimeInit#commonInit(), has
a default no-op implementation of the CompatChanges callback. This
change moves initZipPathValidator() into
ActivityThread#handleBindApplication right after the CompatChanges
callback is set, meaning the compat check starts working as intended.

This change also removes the unit tests and converts them into CTS.

Bug: 268138388
Bug: 268137846
Test: atest CtsSecurityHostTestCases:android.security.cts.host.ZipPathValidatorTest
Change-Id: I539465d818e78a7f1dd4dddbe345331836e09caf