Current logic to check whether a PVC is fully bound are:
1. PVC's volume name is not empty
2. Annotation "pv.kubernetes.io/bind-completed" is properly set
The behavior in the test case only set the annotation, and leave the
volume name to be set by a `FakePVController`.
This will cause a problem for us to run some testcase like scheduler's
perf test, scheduling pod with volume as an example, the first try will
always hit "unbound immediate PersistentVolumeClaims" exception.
As a result, the metric data "schedule_attempts_total", or "scheduling_algorithm_duration_seconds"
will not accurate enough.
Signed-off-by: Dave Chen <dave.chen@arm.com>