[InstCombine] Don't insert instructions before a catch switch

CatchSwitches are not splittable, we cannot insert casts, etc. before
them.

This fixes PR26992.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263874 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed