servo: Merge #19304 - Renamed mach test-perf -submit to --submit (from asajeffrey:test-perf-dash-dash-submit); r=jdm

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The `-submit` option should be `--submit` (2 dashes, not one).

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because they are test infrastructure

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Source-Repo: https://github.com/servo/servo
Source-Revision: 2469808b6e09548e7ac7213474afd29aede3c2bc

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : c588f9117011e2a8f8295656618e9cc840475c46

servo/python/servo/testing_commands.py

@@ -175,7 +175,7 @@ class MachCommands(CommandBase):
              category='testing')
     @CommandArgument('--base', default=None,
                      help="the base URL for testcases")
-    @CommandArgument('-submit', '-a', default=False, action="store_true",
+    @CommandArgument('--submit', '-a', default=False, action="store_true",
                      help="submit the data to perfherder")
     def test_perf(self, base=None, submit=False):
         self.set_software_rendering_env(True)