Fix delta_state_dumps.sh compare order in Linux

[JulianGCalderon]

The script uses ls -trU1 to diff the state dumps in order, so that we can find the first tx that introduced errors in the state (as the following transaction will fail due to the first one).

The flag U in Mac orders by date of creation, but in Linux it does not work that way, resulting in a bad ordering. We should fix this.

The simplest solution is to remove the flag, and order by modification date (default), which works both in Mac and Linux.