Since flutter/engine#17431 and #53739, we observed the following improvements and regressions:

flutter_gallery_ios__transition_perf

• average_frame_rasterizer_time_millis improved from 6ms to 4ms.
• 90th_percentile_frame_rasterizer_time_millis improved from 16ms to 3.7ms probably due to the fix of iOS apps on OpenGL can sometimes get blocked while rendering frames #51809
• 99th_percentile_frame_rasterizer_time_millis regressed from 30ms to 60ms