Previously we had set up the test gerrit instance to use the same
hostname as production: review02.opendev.org. This causes some confusion
as we have to override settings specifically for testing like a reduced
heap size, but then also copy settings from the prod host vars as we
override the host vars entirely. Using a new hostname allows us to use a
different set of host vars with unique values reducing confusion.
Change-Id: I4b95bbe1bde29228164a66f2d3b648062423e294
63f5674e6f