organize more files into folders, and run the weak-mem consistency test as the very first since it is so slow

Author: RalfJung

tests/pass/weak_memory/consistency.rs renamed to tests/pass/0weak_memory_consistency.rs

@@ -214,7 +214,7 @@ fn test_single_thread() {
 }
 
 pub fn main() {
-    for _ in 0..100 {
+    for _ in 0..50 {
         test_single_thread();
         test_mixed_access();
         test_load_buffering_acq_rel();