Changes in 20200914095101

Built from 09390cf1d66716146aeb3112f0ac640e317890d9

..index..
Bug 1664718 N[Core:CSS Parsing and Computation]Allow :is() and :where() to have better error recovery.
Bug 1664446 R[Core:DOM: Editor]Intermittent editor/libeditor/tests/test_bug549262.html | check that we didn't get a scroll - got true, expected false | Page is not scrolled down - got +0, expected 29.399999618530273
Bug 1664459 R[Core:Graphics: WebRender]Simplify WebRender radial gradient shader
Bug 1664479 R[Core:Graphics: WebRender]Optimize cs_blur shader for SWGL
Bug 1639153 A[Core:Javascript: WebAssembly]Optimize indirect calls
Bug 1644691 R[Core:Layout]Intermittent bugs/456219-2.html == bugs/456219-2-ref.html | image comparison, max difference: 10, number of differing pixels: 8
Bug 1662608 R[Firefox Build System:Toolchains]Set -fcrash-diagnostics-dir in build-clang.py
Bug 1664086 R[Toolkit:Form Autofill]Use Fluent to set aria-label for credit card list options in preferences
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Changes to 8 bugs - 6 fixed.