70320 [flutter_tools] make getBuildInfo async (cla: yes, tool)

70323 [flutter_tools] use initially parsed package config for language version, sound mode determination (cla: yes, tool)

70327 [flutter_releases] Flutter 1.22.4 framework cherrypicks (a: tests, cla: yes, d: examples, engine, f: cupertino, f: material design, framework, team, tool)

70334 [flutter_tools] make most integration tests null safe (cla: yes, tool)

70336 Support legacy behavior for –host-vmservice-port and –observatory-port with DDS (cla: yes, tool)

70337 Simplify the flutter_web_plugins plugin registration API. (cla: yes, tool)

70403 Clean up Windows plugin template (cla: yes, tool)