Clamp legacy bisect param max_time_minutes to be in the range [1, 60].

tools/run-bisect-perf-regression.py

Index: tools/run-bisect-perf-regression.py
diff --git a/tools/run-bisect-perf-regression.py b/tools/run-bisect-perf-regression.py
index 7641617c5426bde916ba3730643b729733279f95..63afc10a0b58f52a034ed67b22f3a55de54493f9 100755
--- a/tools/run-bisect-perf-regression.py
+++ b/tools/run-bisect-perf-regression.py
@@ -199,7 +199,8 @@ def _CreateBisectOptionsFromConfig(config):
     opts_dict['truncate_percent'] = int(config['truncate_percent'])
 
   if config['max_time_minutes']:
-    opts_dict['max_time_minutes'] = int(config['max_time_minutes'])
+    opts_dict['max_time_minutes'] = _Clamp(
+        int(config['max_time_minutes']), low=1, high=60)
 
   if config.has_key('use_goma'):
     opts_dict['use_goma'] = config['use_goma']
@@ -238,6 +239,11 @@ def _CreateBisectOptionsFromConfig(config):
   return bisect_perf_regression.BisectOptions.FromDict(opts_dict)
 
 
+def _Clamp(n, low, high):
+  """Clamps a value to a range."""
+  return min(high, max(low, n))
+
+
 def _ParseCloudLinksFromOutput(output):
   html_results_pattern = re.compile(
       r'\s(?P<VALUES>http://storage.googleapis.com/' +