Speed up *TS zip file creation

This also makes the resulting zip files more repeatable -- the file list
is sorted and the entries have static timestamps.

On my machine, this saves ~30 seconds for android-cts.zip, it now takes
less than a second.

Test: m -j cts; compare output from without this change
Change-Id: Ia71e35878ff98ba9775115860530e87eee47739f