Added a new parent class, EmulatorExtraCPUTest. This class contains
tests that verify emulator thread pinning behaviour with various
configuration combinations of cpu_share_set, emulator thread policy, and
pCPU pinning schemes. There are two child classes that inherit from
EmulatorExtraCPUTest, VCPUPinSetEmulatorThreads and
CPUDedicatedEmulatorThreads. These classes contain their relevant
min/max microversions and also control how host pCPU's will be exposed
to the guest VM, either via vcpu_pin_set or cpu_dedicated_set
respetively. This commit is repurposed from an older commit [1], and
updated to work with the current service manager.
[1] https://review.rdoproject.org/r/gitweb?p=openstack/whitebox-tempest-plugin.git;a=blob_plain;f=whitebox_tempest_plugin/api/compute/test_cpu_pinning.py;hb=refs/changes/70/18070/52
Change-Id: If15891f3013ebd8100c77b173e9f573515220a57
4ca0a43234