64258 update TimelineStream in flutter_driver (a: tests, cla: yes, framework, waiting for tree to go green)

64267 [framework] make hit slop based on device pointer kind for drag/pan/scale gestures (a: desktop, cla: yes, f: gestures, framework)

64268 Fix placement for SnackBarBehavior.floating (a: quality, cla: yes, f: material design, framework, severe: regression, waiting for tree to go green)

64271 Make large jumpTo recommend deferred loading (a: images, cla: yes, f: scrolling, framework, perf: memory, severe: performance, waiting for tree to go green)

64273 Remove remaining uses of childToSlot (cla: yes, f: cupertino, f: material design, framework)