[tools] Handle benchmark runs reporting more than one result.

tools/perf-to-html.py

 #!/usr/bin/env python
 # Copyright 2015 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 '''
 python %prog
 
 Convert a perf trybot JSON file into a pleasing HTML page. It can read
 from standard input or via the --filename option. Examples:
 
@@ skipping 97 matching lines @@
 
   def isNotablyNegative(self):
     return self.notable_ < 0
 
 
 class Benchmark:
   def __init__(self, name, data):
     self.name_ = name
     self.tests_ = {}
     for test in data:
-      # strip off "<name>/" prefix
-      test_name = test.split("/")[1]
+      # strip off "<name>/" prefix, allowing for subsequent "/"s
+      test_name = test.split("/", 1)[1]
       self.appendResult(test_name, data[test])
 
   # tests is a dictionary of Results
   def tests(self):
     return self.tests_
 
   def SortedTestKeys(self):
     keys = self.tests_.keys()
     keys.sort()
     t = "Total"
@@ skipping 239 matching lines @@
   parser.add_option("-f", "--filename", dest="filename",
                     help="Specifies the filename for the JSON results "
                          "rather than reading from stdin.")
   parser.add_option("-t", "--title", dest="title",
                     help="Optional title of the web page.")
   parser.add_option("-o", "--output", dest="output",
                     help="Write html output to this file rather than stdout.")
 
   (opts, args) = parser.parse_args()
   Render(opts, args)