31873 Add basic desktop linux checks (cla: yes, tool)

31885 Fix commit message UTF issue for deploy_gallery shard too (cla: yes, team)

31889 Start abstracting platform logic builds behind a shared interface (cla: yes, tool)

31890 apply fp hack to Flex (cla: yes, framework)

31894 Introduce separate HitTestResults for Box and Sliver (cla: yes, framework)

31895 Report CompileTime metric in flutter build aot –report-timings. (cla: yes, tool)

31902 Updated primaryColor docs to refer to colorScheme properties (cla: yes, d: api docs, f: material design, framework)

31903 Extract TODO comment from Image.asset dardoc (cla: yes, d: api docs, framework)