Permit 65535 byte ZIP comments and empty Central Directory

This fixes two cosmetic issues in APK Signature Scheme v2 signature
verifier in Android Package Manager:
* Accept APKs with ZIP End of Central Directory comment of length
  65535. Previously, only comments of length 65534 were accepted due
  to a off by one bug.
* Accept APKs with empty ZIP Central Directory.

These issues should not affect actual APKs because they cannot have an
empty ZIP Central Directory (they must contain at least the
AndroidManifest.xml entry) and shouldn't contain any comments in ZIP
End of Central Directory.

Test: cts-tradefed run singleCommand cts --skip-device-info --skip-preconditions --skip-connectivity-check --abi arm64-v8a --module CtsAppSecurityHostTestCases -t android.appsecurity.cts.PkgInstallSignatureVerificationTest
Change-Id: I461c43472fa97c04e7579d129a6053e44233adb7