Add gpu_core_temperature from REST into GPU stress test

Add library routine to get the core_temperature from REST, and
check that the REST temperature matches the nvidia-smi reported
temperature.

Resolves openbmc/openbmc-test-automation#1355

Change-Id: Ib136054e0dfff16482711e4f8c95eb2b24315558
Signed-off-by: Steven Sombar <ssombar@us.ibm.com>
2 files changed