Revert "[InstCombine] Check inbounds in load/store of gep null transform (PR48577)"

This reverts commit 899faa50.

Upon further consideration, this does not fix the right issue.
Doing this fold for non-inbounds GEPs is legal, because the
resulting pointer is still based-on null, which has no associated
address range, and as such and access to it is UB.

https://bugs.llvm.org/show_bug.cgi?id=48577#c3