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

llvm-svn: 236214