Introduce WPTServe for running W3C Blink Layout tests

Tools/Scripts/webkitpy/common/system/executive.py

Index: Tools/Scripts/webkitpy/common/system/executive.py
diff --git a/Tools/Scripts/webkitpy/common/system/executive.py b/Tools/Scripts/webkitpy/common/system/executive.py
index 5d53ab9b57c7e849a5d100ec5cd8be2064d0061b..5a1d9f6fb73994b0296e42d7cc1a0002d67d49b7 100644
--- a/Tools/Scripts/webkitpy/common/system/executive.py
+++ b/Tools/Scripts/webkitpy/common/system/executive.py
@@ -86,6 +86,7 @@ class ScriptError(Exception):
 class Executive(object):
     PIPE = subprocess.PIPE
     STDOUT = subprocess.STDOUT
+    DEVNULL = open(os.devnull, 'wb')
 
     def _should_close_fds(self):
         # We need to pass close_fds=True to work around Python bug #2320
@@ -423,7 +424,7 @@ class Executive(object):
         # The Windows implementation of Popen cannot handle unicode strings. :(
         return map(self._encode_argument_if_needed, string_args)
 
-    # The only required arugment to popen is named "args", the rest are optional keyword arguments.
+    # The only required argument to popen is named "args", the rest are optional keyword arguments.
     def popen(self, args, **kwargs):
         # FIXME: We should always be stringifying the args, but callers who pass shell=True
         # expect that the exact bytes passed will get passed to the shell (even if they're wrongly encoded).