Reduce resource requirements set aside for testenvs

CPUPerEnv : Because we're not cpu bound overcommitting slightly on CPU
should not cause us any problems.

MemPerEnv : Nodes in testenvs now use the devtest default of 2G.

DiskPerEnv: Each testenv currently uses about 35G of diskspace, setting
aside almost twice should be ok.

Essentially this should cause the number of Test Envs on each R1 host to
increase from 4 to 8 (bound by CPUPerEnv) and on each R2 host from 3 to
6 (bound by MemPerEnv).

Change-Id: Ia45f686d261152f74077259199bc8eab5babe12b
Merge "Reduce resource requirements set aside for testenvs"