Changes in 20201230092946

Built from 0c1bddfaceddf99e5bfacf89d8c08c2aa9ec85db

..index..
Bug 1678652 R[Core:Canvas: WebGL]failIfMajorPerformanceCaveat causes website breakage since 83
Bug 1683226 R[Core:DOM: UI Events & Focus Handling]Get rid of plugin support of IME/keyboard handling
Bug 1351248 N[Core:DOM: UI Events & Focus Handling]Can't tab into or out of fieldset with overflow auto
Bug 1684483 R[Core:GFX: Color Management]Drop some unneeded semicolons.
Bug 1684387 R[Core:GFX: Color Management]Drop an unused libc import
Bug 1684453 R[Core:GFX: Color Management]Handle curveType::Curve in a more Rust like fashion.
Bug 1684192 R[Core:GFX: Color Management]Make some profile creation functions infallible.
Bug 1684091 R[Core:JavaScript Engine: JIT]Replace MOZ_MUST_USE with [[nodiscard]] in js/src/jit/
Bug 1676966 R[Core:Layout: Text and Fonts]Fenix takes longer to reflow wikipedia.org than Fennec, partially due to font initialization
Bug 1682875 R[Firefox:Address Bar][Experiment] The "Switch to Tab" string is not displayed when hovering the Sponsored suggestion if the Amazon website is already opened in a tab from the Awesomebar
Bug 1041377 N[Firefox:Keyboard Navigation]Investigate removing Backspace as a shortcut for navigating back in history
###########
Changes to 11 bugs - 8 fixed.