Re-push "[Option] Fix PR37006 prefix choice in findNearest"

Summary:
Original changeset (https://reviews.llvm.org/D46776) by @modocache. It was
reverted after the PS4 bot failed.

The issue has been determined to be with the way the PS4 SDK handles this
particular option. https://reviews.llvm.org/D50410 removes this test, so we
can push this again.

Patch by Arnaud Coomans!

Reviewers: cfe-commits, modocache

Reviewed By: modocache

Differential Revision: https://reviews.llvm.org/D50515

llvm-svn: 341329