Ansible INVENTORY: machine definitions of test-osuosl-aix72-ppc64-[3,4] need to be removed

[aixtools]

Please put the name of the software product (and affected platforms if relevant) in the title of this issue

Delete as appropriate from this list:

• Missing install
  test-osuosl-aix72-ppc64-3 was never installed

• Double listing
  test-osuosl-aix72-ppc64-4 is actually build-osuosl-aix72-ppc64-1

Details:
In particular, the double listing makes it difficult to determine the actual status of the system - and running two jenkins agents tends to fill the filesystem - bringing "two" nodes down.