Change AWS `large_z1` and `large_z2` from `m1.medium` to `m1.large`

* Every job aside from api_z{1,2} is now in the medium_z{1,2} resource pool
* We did not change the vsphere resource pool definitions, so these other jobs
  now have less local storage space (2GB instead of 10GB).

[Finishes #65213504]

Signed-off-by: Tammer Saleh <tammer@pivotallabs.com>