Fix 3 issues from AI review: timeout after restart, stale case.py, float consistency

- Use common.delete_file instead of raw os.remove for intermediate
  step cleanup (prevents filesystem errors from crashing a passing test)
- Guard finally block's create_directory so it cannot mask the original
  exception on failure
- Use direct case.restart_check instead of getattr with default (fail
  loudly if attribute is removed rather than silently skipping tests)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sbryngelson

toolchain/mfc/test/case.py

@@ -176,12 +176,15 @@ def run_restart(self, targets, gpus):
                 d_dir = os.path.join(dirpath, "D")
                 mid_tag = f"{mid_step:06d}"
                 for f in glob.glob(os.path.join(d_dir, f"*.{mid_tag}.dat")):
-                    os.remove(f)
+                    common.delete_file(f)
 
             return result2
         finally:
             self.params = orig
-            self.create_directory()
+            try:
+                self.create_directory()
+            except Exception:
+                pass
 
     def get_trace(self) -> str:
         return self.trace

toolchain/mfc/test/test.py

@@ -386,7 +386,7 @@ def _handle_case(case: TestCase, devices: typing.Set[int]):
 
         # Restart roundtrip verification: run to midpoint, restart,
         # and compare restarted output against the straight run.
-        if getattr(case, 'restart_check', False) and not ARG("add_new_variables"):
+        if case.restart_check and not ARG("add_new_variables"):
             straight_pack = pack
 
             if timeout_flag.is_set():