Bug 1083073 - Fix update tests when app.update.silent is true by default. r=rstrong a=testonly

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extra : rebase_source : 428ea264032a4c54a500de8cc56c86ea1d4fe974
Bug 1085628 - Fix browser_880164_customization_context_menus.js against smaller toolbars by synthesizing context menu event on first pixel instead of last one. r=Gijs a=testonly

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extra : rebase_source : b6fd795fa1a7f6f50a6db654314f53afcddb25f3
Bug 1083045 - Scratchpad tests shouldn't depend on chrome debugging being disabled by default. r=past a=testonly

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extra : rebase_source : cd607fbfcbf66386e02f8c173746b6828c7e5619