Stop APInt::shl from generating llvm.trap

Stop APInt::shl from generating llvm.trap

APInt::shl generated llvm.trap to guard against shifts greater than bit-width.
This was already checked with an assert, and there was a special case for
shifts equal to bit-width. Modify this check to catch shifts greater than or
equal to bit-width, so llvm.trap isn't generated.

Patch contributed by JF Bastien

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166803 91177308-0d34-0410-b5e6-96231b3b80d8