Fix indexing/memory issue in Tensor3 wrapper

[lebuller]

When indexing along the view wrapper for a Tensor3, there appears to be duplicated memory issue where setting values in certain indices will cause those values to be reproduced across separate indices.
i.e. when creating a wrapper for a 3x3x7 Tensor3 Field, filling the values across (All, All, 0) leads to some of the values on (All, All, 3) and (All, All, 6) to be erroneously filled at the same time.