Remove error when building the same thing twice

This was to prevent bugs leading to loops, but also prevents
rebuilds in case of flaky builds that are manually reset.

Things seem stable enough now, so remove it.

autobuild.py

@@ -485,7 +485,6 @@ def run_build(args: Any) -> None:
     except Exception as e:
         raise SystemExit("ERROR: msys2_root not functional", e)
 
-    done = set()
     while True:
         pkgs = get_buildqueue_with_status(full_details=True)
         update_status(pkgs)
@@ -493,10 +492,6 @@ def run_build(args: Any) -> None:
         if not todo:
             break
         pkg, build_type = todo
-        key = pkg['repo'] + build_type + pkg['name'] + pkg['version']
-        if key in done:
-            raise SystemExit("ERROR: building package again in the same run", pkg)
-        done.add(key)
 
         if (time.monotonic() - start_time) >= SOFT_TIMEOUT:
             print("timeout reached")