While we might never be able to have 100% of our code strict, we can at
the very least do it for all of our tests. This ensures that our tests
are using our API with the types as intended by the test author, and not
silently be cast to what our API requires.
Fix#2442. Although data and styles are handled correctly after removing row(s) or column(s), the dimensions of the removed rows and columns remain behind to afflict their replacements. This PR will take care of removing the dimensions as well.
Dimensions has a _clone method for a deep clone, but all of its properties, as well as the properties of RowDimensions and ColumnDimensions, are scalars, and do not require a deep clone. The method is deleted.