fix bounds bug in getindex(a:b, c:d) with c<1

And more laconic Julia.

Commit 646fe6b3 eliminated a non "redundant bounds check", which is here
re-introduced via `check_indexingrange` function.
Merge pull request #8351 from rfourquet/range-getindex

fix bounds bug in getindex(a:b, c:d) with c<1