PowerVM resize and migrate test cases

Resize and migrate functionality for the PowerVM driver
was landed without tests.

Fixes bug 1133058

Co-authored-by: Matt Riedemann <mriedem@us.ibm.com>
Change-Id: I9b46f092ebaab630fe80e0306ea32bda5a4c1d2f
Merge "PowerVM resize and migrate test cases"