Revert "Allow prefs to be overridden from a file and set WPT-specific…

… prefs from file (#33163)"

This reverts commit e85491b5fc0ccbedfa312b82edf37d8e1cecc780.

tools/wptrunner/wptrunner/executors/executorservo.py

@@ -38,8 +38,6 @@ def __init__(self, logger, browser, server_config, timeout_multiplier, debug_inf
         self.environment = {}
         self.protocol = ConnectionlessProtocol(self, browser)
 
-        self.wpt_prefs_path = self.find_wpt_prefs()
-
         hosts_fd, self.hosts_path = tempfile.mkstemp()
         with os.fdopen(hosts_fd, "w") as f:
             f.write(make_hosts_file(server_config, "127.0.0.1"))
@@ -66,20 +64,6 @@ def on_output(self, line):
         else:
             self.logger.process_output(self.proc.pid, line, " ".join(self.command), self.test.url)
 
-    def find_wpt_prefs(self):
-        default_path = os.path.join("resources", "wpt-prefs.json")
-        # The cwd is the servo repo for `./mach test-wpt`, but on WPT runners
-        # it is the WPT repo. The nightly tar is extracted inside the python
-        # virtual environment within the repo. This means that on WPT runners,
-        # the cwd has the `_venv3/servo` directory inside which we find the
-        # binary and the 'resources' directory.
-        for dir in [".", "./_venv3/servo"]:
-            candidate = os.path.abspath(os.path.join(dir, default_path))
-            if os.path.isfile(candidate):
-                return candidate
-        self.logger.error("Unable to find wpt-prefs.json")
-        return default_path
-
     def build_servo_command(self, test, extra_args=None, debug_opts="replace-surrogates"):
         args = [
             "--hard-fail", "-u", "Servo/wptrunner",
@@ -94,7 +78,6 @@ def build_servo_command(self, test, extra_args=None, debug_opts="replace-surroga
             args += ["--user-stylesheet", stylesheet]
         for pref, value in self.environment.get('prefs', {}).items():
             args += ["--pref", f"{pref}={value}"]
-        args += ["--prefs-file", self.wpt_prefs_path]
         if self.browser.ca_certificate_path:
             args += ["--certificate-path", self.browser.ca_certificate_path]
         if extra_args: