Inherit V2 API's flavors tests from V3 tests

There is a lot of copy&paste test code for Nova v2/v3 API tests.
In addition, we need to add many checks for API test coverage.
As the result, we should apply the same changes to v2 and v3 tests.

This patch reuse the test code of flavors APIs between V2 and V3
Inheriting the V2 flavors API's test from V3 tests.

Partially implements blueprint nova-api-test-inheritance

Change-Id: I85463baec7af1e4e8bcc6310804fd15c1958d7ed
create test and worker summary report

a summary report that includes counts of the test results so far
as well as a worker report to let us understand how our workers
are balanced at the moment, as well as if we are missing worker
0 in our data (which seems to happen quite often).

Change-Id: Ide0b63b86e87f8a18c2f0e45264692ac3797c791
Updated from global requirements

Change-Id: Id92e2cf3977c22b3d283948d2cbcde50e8dfdab5
Merge "create test and worker summary report"
Merge "Inherit V2 API's flavors tests from V3 tests"
Merge "Updated from global requirements"
Merge branch 'master' of https://github.com/openstack/tempest