Revert "[Order Files] Remove dtrace predicate"

This reverts commit r277487.

Removing the probe predicate was a red herring. It results in more symbols being placed in the final order file, but they are symbols from outside the clang image.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@277492 91177308-0d34-0410-b5e6-96231b3b80d8