Changes in 20210606214208

Built from b8840fca4819c88bbad851f4c2cf76e448d970d3

..index..
Bug 1713787 N[Core:CSS Parsing and Computation]Fix some CSS-variables tests.
Bug 1714457 N[Core:CSS Parsing and Computation]Make all predefined symbolic counter styles not overwritable
Bug 1714631 R[Core:Layout: Form Controls]Misaligned input placeholder
Bug 1710034 R[Core:Panning and Zooming]choose a double tap rect for replaced elements that are not too tall that includes their full height, not just their width
Bug 1714351 A[Firefox:General]Remove and reconcile -moz-proton-doorhangers media queries
Bug 1710237 R[Firefox:Tabbed Browser]Can't click on a portion of a pinned tab with Picture-In-Picture opened when the tab is not playing sound (but no tab mute state has been set)
Bug 1709640 A[GeckoView:General]Add GeckoView lite build type
Bug 1714686 R[Release Engineering:General]Temporarily disable libjxl updates
Bug 1706391 R[Toolkit:Blocklist Implementation]Remove blocklist v2 and blocklist v3 prefs on desktop
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Changes to 9 bugs - 5 fixed.