Auto merge of #15990 - vlisivka:master, r=emilio

Layout viewer now uses local copy of jquery. See #15964.

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Layout viewer now uses local copy of jquery as requested in ticket, so etc/layout_viewer/viewer.html can work without connection to the internet.

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<!-- 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 #15964(github issue number if applicable).

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- [ ] There are tests for these changes OR
- [x] These changes do not require tests because changes are tested manually by unplugging the internet connection.

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etc/layout_viewer/viewer.html

@@ -80,7 +80,7 @@
         </div>
 
         <!-- jQuery -->
-        <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
+        <script src="js/jquery.min.js"></script>
         <!-- Bootstrap -->
         <script src="js/bootstrap.min.js"></script>
         <!-- Treeview -->