[benchmark] NFC: Turn benchmark ON on all non-Windows buildbots

The problems with benchmark build should be fixed now, but Windows
buildbots still run into errors seemingly because of the bug in
clang-cl. Because of that, benchmark shouldn't be built on Windows at
this point.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@340905 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed