This removes the old rest_tests and adds significantly more coverage.
Maybe too much. The v4,v6 and v6,v4 tables are identical but for the
order of families.
This exposed that `trimFieldsForDualStackDowngrade` is called too late
to do anything (since we don't run strategy twice any more). I moved
similar logic to `PatchAllocatedValues` but I hit on some unclarity.
Specifically, consider a PATCH operation.
Assume I have a valid dual-stack service (with 2 IPs, 2 families, and
policy either require or prefer). What fields can I patch, on their own,
to trigger a downgrade to single-stack?
I think patching policy to "single" is pretty clear intent.
But what if I leave policy and only patch `ipFamilies` down to a single
value (without violating the "can't change first family" rule)?
Or what if I patch `clusterIPs` down to a single IP value?
After much discussion, we decided to make a small API change (OK since
we are beta). When you want a dual-stack Service you MUST specify the
`ipFamilyPolicy`. Now we can infer less and avoid ambiguity.
ca8cfdcae9