_getfailureheadline: get head_line property only once

src/_pytest/terminal.py

@@ -734,10 +734,10 @@ class TerminalReporter(object):
         return res + " "
 
     def _getfailureheadline(self, rep):
-        if rep.head_line:
-            return rep.head_line
-        else:
-            return "test session"  # XXX?
+        head_line = rep.head_line
+        if head_line:
+            return head_line
+        return "test session"  # XXX?
 
     def _getcrashline(self, rep):
         try: