Bug 1605283 - Improve support for invalidation debugging and testing …

…r=nataliaCs

Differential Revision: https://phabricator.services.mozilla.com/D61207

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/388a4d04e91159527a69fa1e3d2a91e7155247aa

tileview/src/main.rs

@@ -157,7 +157,6 @@ fn tile_to_svg(key: TileOffset,
             };
 
         svg += &format!("<rect x=\"{:.2}\" y=\"{:.2}\" width=\"{:.2}\" height=\"{:.2}\" {}/>",
-                        svg,
                         rect_world.origin.x,
                         rect_world.origin.y,
                         rect_world.size.width,