This spec tests `reshape()` with more cases than the one in
test/utils/array.test.js, including various types.
Also, in `_reshape()`, throw a brand new `DimensionError` instead of
modifying the caught one (the error message does not change when other
attributes are modified, as it is computed when the error is created).
`reshape()` takes an n-d array and a list of sizes for each dimension,
and fits the data into the specified shape. If the product of the sizes
of the new dimensions does not match that of the old, a DimensionError
is thrown.
