Remove deprecated and unused run_and_throw_if_fail from webkitpy

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

Index: Tools/Scripts/webkitpy/common/system/executive_mock.py
diff --git a/Tools/Scripts/webkitpy/common/system/executive_mock.py b/Tools/Scripts/webkitpy/common/system/executive_mock.py
index aa855d75d1391efe101348089f1123e2c2001015..1f137de283b0539e26882ab0d0be7cd13053e5c5 100644
--- a/Tools/Scripts/webkitpy/common/system/executive_mock.py
+++ b/Tools/Scripts/webkitpy/common/system/executive_mock.py
@@ -82,17 +82,6 @@ class MockExecutive(object):
         _log.info("MOCK running_pids: %s" % running_pids)
         return running_pids
 
-    def run_and_throw_if_fail(self, args, quiet=False, cwd=None, env=None):
-        self.calls.append(args)
-        if self._should_log:
-            env_string = ""
-            if env:
-                env_string = ", env=%s" % env
-            _log.info("MOCK run_and_throw_if_fail: %s, cwd=%s%s" % (args, cwd, env_string))
-        if self._should_throw_when_run.intersection(args):
-            raise ScriptError("Exception for %s" % args, output="MOCK command output")
-        return "MOCK output of child process"
-
     def command_for_printing(self, args):
         string_args = map(unicode, args)
         return " ".join(string_args)