Previously it was following a wrong order by doing `zipalign` after
calling SignApk, which effectively compromised the signature. This CL
corrects the logic, and follows the same flow as in build system:
- Pack APEX file;
- `zipalign -f 4096`;
- Call SignApk to sign the container with `-a 4096` flag.
Bug: 129148142
Test: Run sign_target_files_apks.py on taimen target_files.zip. Boot the
image after signing.
Change-Id: I91bd3dce4f45c1891c5e122212a699f4808618fa
(cherry picked from commit 0e06cb0a8b)
ffc9a30946