Add unit test for Process>>indexOfSP: primitive fix
Add unit test for Process>>indexOfSP: primitive fix

jgfoster/Dolphin,dolphinsmalltalk/Dolphin,objectarts/Dolphin,objectarts/Dolphin,jgfoster/Dolphin,dolphinsmalltalk/Dolphin,jgfoster/Dolphin,jgfoster/Dolphin,dolphinsmalltalk/Dolphin,dolphinsmalltalk/Dolphin