Don't use all the #ifdefs to hide the stats counters and instead rely on

Don't use all the #ifdefs to hide the stats counters and instead rely on
their being optimized out in debug mode. Realistically, this just isn't
going to be the slow part anyways. This also fixes unused variable
warnings that are breaking LLD build bots. =/ I didn't see these at
first, and kept losing track of the fact that they were broken.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187297 91177308-0d34-0410-b5e6-96231b3b80d8