Revert "Evaluate (-1)**((-1)**n/2 -/+ S.Half) as (-1)**n or (-1)**(n + 1)"

This reverts commit fdb8e3ed6b0dd5d9c5855a1021ca7a8a680351cb.
Refine (-1)**((-1)**n/2 -/+ S.Half) as (-1)**n or (-1)**(n + 1)
Adopt Wester test_I4 (use refine)