tests: Add tests for DRAM low power modes

This patch adds two regression tests that execute the script in the
configs dir for triggering low power mode transitions. A separate
test is required for each page policy because for close-adaptive
page policy the DRAM goes into the Precharge Power-down mode while
for open-adaptive page policy it goes into the Activate Power-down
mode.

Change-Id: Iad61af23f132db046f2857cc3ef64b2bf42cf5e4
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/5726
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

stats: update references

stats: update stats for thermals, indirect BP

stats: update stats to after GPU checkin

stats: updates due to recent chagnesets

stats: updates due to recent changes.

stats: changes to due to recent set of patches

stats: updates due to changes to x86, stale configs.

stats: updates due to recent ruby and x86 changes
Also updates many out of date config files.

tests: Reflect name change in DRAM tests

This patch reflects the recent name change in the DRAM TrafficGen
tests and also tidies up the test directory.