50846 Add additional focus samples. (cla: yes, d: api docs, d: examples, documentation, f: focus, framework, waiting for tree to go green)

50849 Roll engine d60f298d9e77..bb01cb7faf26 (11 commits) (cla: yes, waiting for tree to go green)

50851 Animated placeholder perf (cla: yes, team, waiting for tree to go green)

50853 Revert “[version] Update to the latest test package” (cla: yes, team, tool)

50872 [flutter_tools] fix debug stack traces (cla: yes, tool)

50877 [flutter_tools] include depfile outputs in gradle outputs (cla: yes, tool)

50879 [versions] reland update test to 1.12.0 (cla: yes, team, tool)