Auto merge of #12375 - gpoesia:master, r=KiChjang

Implement Runnable::name() for ImageResponseHandlerRunnable

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Implement the name() method from the Runnable trait for ImageResponseHandlerRunnable.

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- [X] These changes fix #12345 (github issue number if applicable).

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components/script/dom/htmlimageelement.rs

@@ -81,6 +81,8 @@ impl ImageResponseHandlerRunnable {
 }
 
 impl Runnable for ImageResponseHandlerRunnable {
+    fn name(&self) -> &'static str { "ImageResponseHandlerRunnable" }
+
     fn handler(self: Box<Self>) {
         // Update the image field
         let element = self.element.root();