Backport 1477259 - Use different Android Version Codes in x86 and aarch64 packages

In Fennec 60, Mozilla assigned the x86 and aarch64 packages identical version codes. Mozilla didn't upload aarch64 packages onto Google Play (or any other app store), so they never noticed the conflict. They resolved this in bug 1477259 by changing how the version numbers are computed, but it landed after 60esr and it wasn't uplifted. Now we need this patch before August 1.