[cts content tests] use v4 flag instead of prebuilt APKs

Cleaning up prebuilt APKs/idsig files.

Will move v2/v3 tests to cts/appsecurity. Will merge
PackageManagerShellCommand*Test in a follow-up CL.

BUG: 149354175
Test: atest PackageManagerShellCommandIncrementalTest
Test: atest PackageManagerShellCommandTest
Change-Id: I0363c9c1d89a6ee540d0bc6fe6e4918ad4fcde5e
10 files changed