Use ScrollView in examples a manual_tests - #7645

@Hixie

LGTM.

Summary of our discussion around this:

• we won't include the shrine demo yet
• there are three bugs to look into:
  • why does it go past the max scroll offset?
  • can we fix the numeric issue with the android simulation whereby it's not idempotent (if you create it with its current velocity, you get a different velocity)
  • can we figure out some magic way to avoid the missed frame when recreating the ballistic simulation?

This patch substantially improved the performance of the microbenchmarks.stock_animation_subsequent_frame and microbenchmarks.stock_animation_close_first_frame benchmarks.

It also increased code size for complex_layout aot_snapshot_size_instructions, but I expect that to reduce when we delete the old code which I presume is still somehow getting linked in here.