Reland "[test] Fix cctest path separators on Windows"

test/intl/testcfg.py

 # Copyright 2013 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 28 matching lines @@
   def ListTests(self, context):
     tests = []
     for dirname, dirs, files in os.walk(self.root):
       for dotted in [x for x in dirs if x.startswith('.')]:
         dirs.remove(dotted)
       dirs.sort()
       files.sort()
       for filename in files:
         if (filename.endswith(".js") and filename != "assert.js" and
             filename != "utils.js"):
-          testname = os.path.join(dirname[len(self.root) + 1:], filename[:-3])
+          fullpath = os.path.join(dirname, filename)
+          relpath = fullpath[len(self.root) + 1 : -3]
+          testname = relpath.replace(os.path.sep, "/")
           test = testcase.TestCase(self, testname)
           tests.append(test)
     return tests
 
   def GetFlagsForTestCase(self, testcase, context):
     flags = ["--allow-natives-syntax"] + context.mode_flags
 
     files = []
     files.append(os.path.join(self.root, "assert.js"))
     files.append(os.path.join(self.root, "utils.js"))
     files.append(os.path.join(self.root, testcase.path + self.suffix()))
 
     flags += files
     if context.isolates:
       flags.append("--isolate")
       flags += files
 
     return testcase.flags + flags
 
 
 def GetSuite(name, root):
   return IntlTestSuite(name, root)