Nest multiple 'resolving hash xxx' steps under a single super step.

scripts/slave/recipe_modules/auto_bisect/bisector.py

Index: scripts/slave/recipe_modules/auto_bisect/bisector.py
diff --git a/scripts/slave/recipe_modules/auto_bisect/bisector.py b/scripts/slave/recipe_modules/auto_bisect/bisector.py
index cd46eb187fbc2b818e67509b6c6a9350f9519313..b0be9bed23029c75e4711a18231b7b63a3ffd856 100644
--- a/scripts/slave/recipe_modules/auto_bisect/bisector.py
+++ b/scripts/slave/recipe_modules/auto_bisect/bisector.py
@@ -648,7 +648,8 @@ class Bisector(object):
   def _revision_value_table(self):
     """Returns a string table showing revisions and their values."""
     header = [['Revision', 'Values']]
-    rows = [[r.revision_string(), str(r.values)] for r in self.revisions]
+    with self._api.m.step.nest('Resolving hashes'):
+      rows = [[r.revision_string(), str(r.values)] for r in self.revisions]
     return self._pretty_table(header + rows)
 
   def _pretty_table(self, data):