Store proxy handlers in a static array rather than a hashtable per window.
Remove references to WindowProxy as an interface.
Add a test for interfaces exposed on the window object.
Stop exposing XMLHttpRequestEventTarget on the window object.
Handle exceptions from JS_ParseJSON in XMLHttpRequest.response.
Merge pull request #2810 from Ms2ger/proxy-handlers

Store proxy handlers in a static array rather than a hashtable per window.
Merge pull request #2813 from Ms2ger/WindowProxy

Remove references to WindowProxy as an interface.
Merge pull request #2815 from Ms2ger/test_interfaces

Add test_interfaces.html.
Merge pull request #2817 from Ms2ger/xhr-response-json

Handle exceptions from JS_ParseJSON in XMLHttpRequest.response.
Update the rust-mozjs submodule pointer.