Dont slow down everyone else's testing (especially the CI's Linux) just for OS X.

Namely, the allowance for up to 7 events, and thus requiring anyone
with fewer than 7 events to wait for the 3 second timeout, is only
relevant to fsevents (i.e. Mac OS X)

crates/ra_vfs/tests/vfs.rs

@@ -83,7 +83,7 @@ fn test_vfs_works() -> std::io::Result<()> {
     }
 
     // rust-analyzer#734: fsevents has a bunch of events still sitting around.
-    process_tasks_in_range(&mut vfs, 0, 7);
+    process_tasks_in_range(&mut vfs, 0, if cfg!(target_os = "macos") { 7 } else { 0 });
     match vfs.commit_changes().as_slice() {
         [] => {}