Auto merge of #26229 - servo:jdm-patch-36, r=SimonSapin

Use python binary to run multiprocess tests.

The python2 binary doesn't exist in the path on macOS. This change uses an existing python2 on macOS and whatever the default python version is on linux.

etc/taskcluster/decision_task.py

@@ -614,7 +614,7 @@ def wpt_chunks(platform, make_chunk_task, build_task, total_chunks, processes,
         # https://github.com/servo/servo/issues/22438
         if this_chunk == 0:
             task.with_script("""
-                time python2 ./mach test-wpt --release --binary-arg=--multiprocess \
+                time python ./mach test-wpt --release --binary-arg=--multiprocess \
                     --processes $PROCESSES \
                     --log-raw test-wpt-mp.log \
                     --log-errorsummary wpt-mp-errorsummary.log \

etc/taskcluster/decisionlib.py

@@ -685,7 +685,7 @@ class MacOsGenericWorkerTask(UnixTaskMixin, GenericWorkerTask):
         # So concatenate scripts and use a single `bash` command instead.
         return [
             [
-                "/bin/bash", "--login", "-x", "-e", "-c",
+                "/bin/bash", "--login", "-x", "-e", "-o", "pipefail", "-c",
                 deindent("\n".join(self.scripts))
             ]
         ]
@@ -749,7 +749,7 @@ class DockerWorkerTask(UnixTaskMixin, Task):
             "image": self.docker_image,
             "maxRunTime": self.max_run_time_minutes * 60,
             "command": [
-                "/bin/bash", "--login", "-x", "-e", "-c",
+                "/bin/bash", "--login", "-x", "-e", "-o", "pipefail", "-c",
                 deindent("\n".join(self.scripts))
             ],
         }

tests/wpt/metadata/MANIFEST.json

@@ -345756,7 +345756,7 @@
         []
        ],
        "executorservodriver.py": [
-        "425f40223f77535d4ea34d75790e8facce30f77a",
+        "2e47a22a9c92b4caada29db358c08104793d2770",
         []
        ],
        "executorwebdriver.py": [

tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/executors/executorservodriver.py

@@ -277,7 +277,7 @@ class ServoWebDriverRefTestExecutor(RefTestExecutor):
 
         return ServoWebDriverRun(self.logger,
                                  self._screenshot,
-                                 self.protocol.session,
+                                 self.protocol,
                                  self.test_url(test),
                                  timeout,
                                  self.extra_timeout).run()