Handle tests that just won't stop

tests/run-tests.py

@@ -183,7 +183,17 @@ def run_micropython(pyb, args, test_file, is_special=False):
 
             # run the actual test
             try:
-                output_mupy = subprocess.check_output(cmdlist, stderr=subprocess.STDOUT)
+                result = subprocess.run(
+                    cmdlist,
+                    stderr=subprocess.STDOUT,
+                    stdout=subprocess.PIPE,
+                    check=True,
+                    timeout=10,
+                )
+                output_mupy = result.stdout
+            except subprocess.TimeoutExpired as er:
+                had_crash = True
+                output_mupy = (er.output or b"") + b"TIMEOUT"
             except subprocess.CalledProcessError as er:
                 had_crash = True
                 output_mupy = er.output + b"CRASH"
@@ -869,7 +879,7 @@ the last matching regex is used:
         tests = args.files
 
     if not args.keep_path:
-        # clear search path to make sure tests use only builtin modules and those in extmod
+        # clear search path to make sure tests use only builtin modules and those that can be frozen
         os.environ["MICROPYPATH"] = os.pathsep.join(
             [
                 "",