Remove couple of methods by using built-in sort

The key in the array-to-sort is an alphanumeric id, that will continue to
grow as time passes. We can (and already do in other places in the code)
just use a built-in key sort, which will be faster.

This wil the only use for compareCreateTime, which in turn was the only
method calling getNumber. Both are now removed.

Change-Id: Id0269de6a7d01bb19e264f6fbec4ab6c08cb6f6b
Merge "Remove couple of methods by using built-in sort"