Correct extractelement constant folding

Summary: Constant folding of extractelement with out-of-bound index produces undef also for indexes bigger than 64bit (instead of crash assert failure as before)

Test Plan: Unit tests included.

Reviewers: majnemer

Reviewed By: majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9225

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235700 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed