77432 [flutter_tools] remove most globals from resident web runner (cla: yes, tool, waiting for tree to go green)

77434 Enable unnecessary_await_in_return lint (a: tests, cla: yes, f: material design, framework, team, tool, waiting for tree to go green)

77559 Remove “unnecessary” import in build_appbundle_test (cla: yes, tool)

77566 Increase timeouts to fix build integration timeout flakes (cla: yes, tool)

77651 [fuchsia] remove no devices found from ffx parsing (cla: yes, team, tool, waiting for tree to go green)

77664 Move iOS codesigning into assemble build target (cla: yes, platform-ios, t: xcode, tool)

77727 [flutter_tools] simplify platform null safety (cla: yes, tool)