Add convenient overloads for CreateInsertElement and CreateExtractElement methods...

Add convenient overloads for CreateInsertElement and CreateExtractElement methods in IRBuilder

Summary:
This pathc add convenient overloads for CreateInsertElement and CreateExtractElement methods in IRBuilder
where vector index can be uint64_t instead of Value*.

Test Plan: Unit test included.

Reviewers: majnemer

Reviewed By: majnemer

Subscribers: majnemer, llvm-commits

Differential Revision: http://reviews.llvm.org/D9347

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236214 91177308-0d34-0410-b5e6-96231b3b80d8