[Driver] Loosen test for LLVM findNearest

Summary:
When https://reviews.llvm.org/D46776 landed to improve the behavior of
`llvm::OptTable::findNearest`, a PS4 buildbot began failing due to an
assertion that a suggestion "-debug-info-macro" should be provided for
the unrecognized option `clang -cc1as -debug-info-macros`. All other
buildbots succeeded in this check, and the PS4 buildbot succeeded in the
other `findNearest` tests.

Temporarily loosen this check in order to reland the `findNearest`
change.

Test Plan: check-clang

llvm-svn: 332804