Prefix `on` for function name of inline events
While checking what needs to be done for the spec-update, I've noticed the logic of checking `is window-reflecting element (e.g. body and frameset)` is already handled by the `is` casting function.
However, we still failed to pass the tests because we're missing `on` prefix for inline functions.
I'm not sure if this patch is good enough (or maybe at least I need to add a comment for why adding `on` prefix?).
Besides, I checked [how Gecko handles](https://searchfox.org/mozilla-central/rev/8bc4e35c9bb47c1fe3131e6155d9f482e1efef9a/dom/events/EventListenerManager.cpp#1012-1022) and looks like they also just pass the atom directly.
But, the [generated atom](https://searchfox.org/mozilla-central/source/__GENERATED__/xpcom/ds/nsGkAtomList.h#775) is prefixed with `on` which is correct to just pass it into the `CompileFunction`.
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Fix radial gradients for html canvas element
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The latest version of raqote provides a fix for properly handling boundary conditions for TwoCircleRadialGradients.
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