flagCrossStatistics dont work as expected

the latest changes to flagCrossStatictics changed the behavior a lot !

before the change it was able to flag all columns that was given even if they have different indexes. this was the charm of it.

Now it enforce harmonized index and also fails [1] during checking this :(

i somewhat rely on the function in GECF..

[1]

Stacktrace (Click to expand)

  File "scripts/qc_cross_P.py", line 43, in process
    qc = qc.flagCrossStatistics(field=hasroof, thresh=3.5, flag=f.DOUBT)
  File "/home/palmb/.virtualenvs/gcef_pipeline/lib/python3.8/site-packages/saqc/core/modules/outliers.py", line 114, in flagCrossStatistics
    return self._defer("flagCrossStatistics", locals())
  File "/home/palmb/.virtualenvs/gcef_pipeline/lib/python3.8/site-packages/saqc/core/modules/__init__.py", line 45, in _defer
    return self._wrap(FUNC_MAP[fname])(**flocals, **fkwargs)
  File "/home/palmb/.virtualenvs/gcef_pipeline/lib/python3.8/site-packages/saqc/core/core.py", line 215, in inner
    out = out._callFunction(
  File "/home/palmb/.virtualenvs/gcef_pipeline/lib/python3.8/site-packages/saqc/core/core.py", line 242, in _callFunction
    res = function(data=self._data, flags=self._flags, field=field, *args, **kwargs)
  File "/home/palmb/.virtualenvs/gcef_pipeline/lib/python3.8/site-packages/saqc/core/register.py", line 155, in __call__
    data, flags = self.func(*args, **kwargs)
  File "/home/palmb/.virtualenvs/gcef_pipeline/lib/python3.8/site-packages/saqc/funcs/outliers.py", line 1268, in flagCrossStatistics
    if (data[src].index != data[fields[0]].index).any():
  File "/home/palmb/.virtualenvs/gcef_pipeline/lib/python3.8/site-packages/pandas/core/indexes/extension.py", line 156, in wrapper
    return op(other)
  File "/home/palmb/.virtualenvs/gcef_pipeline/lib/python3.8/site-packages/pandas/core/ops/common.py", line 69, in new_method
    return method(self, other)
  File "/home/palmb/.virtualenvs/gcef_pipeline/lib/python3.8/site-packages/pandas/core/arraylike.py", line 36, in __ne__
    return self._cmp_method(other, operator.ne)
  File "/home/palmb/.virtualenvs/gcef_pipeline/lib/python3.8/site-packages/pandas/core/arrays/datetimelike.py", line 1008, in _cmp_method
    other = self._validate_comparison_value(other)
  File "/home/palmb/.virtualenvs/gcef_pipeline/lib/python3.8/site-packages/pandas/core/arrays/datetimelike.py", line 549, in _validate_comparison_value
    raise ValueError("Lengths must match")
ValueError: Lengths must match