releasetools: zipalign Trichrome APK after patching

* This was needed to 'adb install' any patched APKs sign out of band
* _might_ not be needed here if this gets done by some other step,
  but if not, doesn't hurt.
* Done by original script too

Change-Id: Ib11f0482b3e134b72bccf08f4c71f5e7e0b8b26c