[LoopInterchange] Update code to use range-based for loops (NFC).
[LoopInterchange] Update code to use range-based for loops (NFC).

Summary:
The remaining non range-based for loops do not iterate over full ranges,
so leave them as they are.

Reviewers: karthikthecool, blitz.opensource, mcrosier, mkuper, aemerson

Reviewed By: aemerson

Subscribers: aemerson, mzolotukhin, llvm-commits

Differential Revision: https://reviews.llvm.org/D35777

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@308872 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm