80549 Migrate xcodeproj to null safety (team, tool, cla: yes, waiting for tree to go green, a: null-safety)

80600 Standardize how Java8 is set in gradle files (team, tool, a: accessibility, cla: yes, d: examples, waiting for tree to go green)

80602 Stop the DevTools child process if the runner terminates unexpectedly (tool, cla: yes, waiting for tree to go green)

80605 Refactor LocalizationsGenerator initialize instance method into factory (team, tool, cla: yes, waiting for tree to go green, a: null-safety)

80614 Migrate xcode.dart and xcode_validator.dart to null safety (team, tool, cla: yes, waiting for tree to go green, a: null-safety)