Revert "[Option] Fix PR37006 prefix choice in findNearest"

Summary:
This revision causes build failures in PS4 and ppc64le buildbots (for example,
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/29988).
I'll revert for now and try to diagnose the issue.

Test Plan: check-llvm check-clang

llvm-svn: 332304