92861 Remove globals_null_migrated.dart, move into globals.dart (a: text input, tool, cla: yes, waiting for tree to go green, integration_test, a: null-safety)

92866 Roll Engine from 98e3216ab470 to 2ea889c9af5c (1 revision) (cla: yes, waiting for tree to go green)

92868 Roll Engine from 2ea889c9af5c to 7797c76bb99c (1 revision) (cla: yes, waiting for tree to go green)

92869 Migrate build_system targets to null safety (tool, cla: yes, waiting for tree to go green, a: null-safety, tech-debt)