fast cdef type indexing into lists/tuples via runtime type checking
fast cdef type indexing into lists/tuples via runtime type checking

- 5 times as fast for L[i], list/tuple L, cdef integer type i, 0 <= i < len(L)
- no change for L[a], python object a
- 1-1.5% slowdown for L[i], i negative or out of range

bhy/cython-haoyu,bhy/cython-haoyu,bhy/cython-haoyu,bhy/cython-haoyu