Auto merge of #11196 - fduraffourg:master, r=jdm

Add unit tests for cookies handling

Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data:
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #9965

Either:
- [X] There are tests for these changes OR
- [ ] These changes do not require tests because _____

Add unit tests for the `net` component about cookies. The tests are generated
with a new `mach update-net-cookies` command from this repo: https://github.com/abarth/http-state.

This PR also includes two trivial bug fixes about cookie handling.

From all the tests included, the following ones are currently failing:

- cookie_http_state::test_0003
- cookie_http_state::test_0006
- cookie_http_state::test_attribute0004
- cookie_http_state::test_attribute0005
- cookie_http_state::test_attribute0007
- cookie_http_state::test_attribute0008
- cookie_http_state::test_domain0017
- cookie_http_state::test_mozilla0001
- cookie_http_state::test_mozilla0002
- cookie_http_state::test_mozilla0003
- cookie_http_state::test_mozilla0005
- cookie_http_state::test_mozilla0007
- cookie_http_state::test_mozilla0009
- cookie_http_state::test_mozilla0010
- cookie_http_state::test_mozilla0013

`test_000[36]` and `test_mozilla*` are failing because there is currently no
method to clean a `net::cookie_storage` from expired cookies.

`test_attribute000[4578]` are failing because hyper does not parse the `Secure`
attribute correctly. I will open an issue on the upstream project.

`test_domain0017` fails because the TLD .org is not on the PUB_DOMAINS list.

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python/servo/testing_commands.py

@@ -664,3 +664,15 @@ testing/web-platform/mozilla/tests for Servo-only tests""" % reference_path)
 
         if editor:
             proc.wait()
+
+    @Command('update-net-cookies',
+             description='Update the net unit tests with cookie tests from http-state',
+             category='testing')
+    def update_net_cookies(self):
+        cache_dir = path.join(self.config["tools"]["cache-dir"], "tests")
+        run_file = path.abspath(path.join(PROJECT_TOPLEVEL_PATH,
+                                          "tests", "unit", "net",
+                                          "cookie_http_state_utils.py"))
+        run_globals = {"__file__": run_file}
+        execfile(run_file, run_globals)
+        return run_globals["update_test_file"](cache_dir)