NFC: Pass DataLayout into isBytewiseValue

Summary:
We will need to handle IntToPtr which I will submit in a separate patch as it's
not going to be NFC.

Reviewers: eugenis, pcc

Reviewed By: eugenis

Subscribers: hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D63940

llvm-svn: 365709