Array.insert fails if labels are ambiguous AND values has the axis

[gdementen]

>>> arr = ndtest('axis1=x1..x3;axis2=x1..x3')
>>> arr.insert(arr['axis1[x1,x2]'], before='axis1[x3]')
ValueError: ['x1'] is ambiguous (valid in axis1, axis2)

>>> # it works if the values has not the axis
>>> arr.insert(arr['axis1[x1]'], before='axis1[x3]', label='x1')
axis1\axis2  x1  x2  x3
         x1   0   1   2
         x2   3   4   5
         x1   0   1   2
         x3   6   7   8
>>> # it works if the labels are not ambiguous
>>> arr2 = arr.set_labels('axis2', str.upper)
>>> arr2.insert(arr2['axis1[x2,x1]'], before='axis1[x3]')
axis1\axis2  X1  X2  X3
         x1   0   1   2
         x2   3   4   5
         x2   3   4   5
         x1   0   1   2
         x3   6   7   8

[gdementen]

see also #879

[gdementen]

In fact, the condition for the bug was if the added labels (from value) were ambiguous in value. This was fixed in 816aeed