TBR: Shorten the number of days we use for the reg test by default.
TBR: Shorten the number of days we use for the reg test by default.

Older dates don't currently pass.  I had set environment variables to
adjust the config in the jenkins test, but these don't seem to apply to
the presubmits.

Change-Id: I449e26545638e539dfedfd87fe720b2bb8200e4e

vanadium/go.jiri,vanadium/go.jiri