Auto merge of #807 - RalfJung:test-name, r=RalfJung

better name for a test: threads -> sync

Author: bors

tests/run-pass/threads.rs renamed to tests/run-pass/sync.rs

@@ -8,8 +8,7 @@ fn main() {
     drop(m.lock());
     drop(m);
 
-    // We don't provide RwLock on Windows
-    #[cfg(not(target_os = "windows"))]
+    #[cfg(not(target_os = "windows"))] // TODO: implement RwLock on Windows
     {
         let rw = sync::RwLock::new(0);
         drop(rw.read());