BUG: provide SparseArray creation in a platform independent manner
makes creation w/o specifying a dtype choose `np.int64/float64` regardless of the platform. This is similar to how Series works. This only is exposed on windows (as the default ndarray creation is np.int32) rather than np.int64

maybe _should_ use `pandas.core.series._sanitize_array` (but needs some tweeks I think).

cc @sinhrks 
