TestPVCClonePerformance fails in ODF 4.18

[manuelgotin]

The following test fails in ODF 4.18:

• test_pvc_clone_performance.py::TestPVCClonePerformance

There are actually 2 issues with this test:

• PVC failed reaching Bound on time - this issue is tracked already here: Exception: PVC failed reaching Bound on time #11174
• subsequently, 'tests/cross_functional/performance/csi_tests/test_pvc_clone_performance.py:82 in analyse_results' fails with StatisticsError

The error log is the following:

'''

---

tests/cross_functional/performance/csi_tests/test_pvc_clone_performance.py:82: in analyse_results
avg_data[op] = statistics.mean(all_data[op])

---

data = []

def mean(data):
    """Return the sample arithmetic mean of data.

    >>> mean([1, 2, 3, 4, 4])
    2.8

    >>> from fractions import Fraction as F
    >>> mean([F(3, 7), F(1, 21), F(5, 3), F(1, 3)])
    Fraction(13, 21)

    >>> from decimal import Decimal as D
    >>> mean([D("0.5"), D("0.75"), D("0.625"), D("0.375")])
    Decimal('0.5625')

    If ``data`` is empty, StatisticsError will be raised.
    """
    if iter(data) is data:
        data = list(data)
    n = len(data)
    if n < 1:

> raise StatisticsError('mean requires at least one data point')
E statistics.StatisticsError: mean requires at least one data point
'''