Mutate break to return to avoid timeouts

Author: boxed

mutmut/__init__.py

@@ -165,7 +165,7 @@ def keyword_mutation(value, context, **_):
         'not': '',
         'is': 'is not',  # this will cause "is not not" sometimes, so there's a hack to fix that later
         'in': 'not in',
-        'break': 'continue',
+        'break': 'return',
         'continue': 'break',
         'True': 'False',
         'False': 'True',