Removing all futures::executor::block_on

[Xuanwo]

block_on is a problem proven insides tokio async context, it's better to remove them all:

• Remove all block_on in our codebase.
  • refactor: Remove usage of futures block_on in tests #6930
• Remove executor features from the futures crate so that we will not use it anymore

[Xuanwo]

/assignme

[Xuanwo]

This issue may be overlap with #4361, ping @youngsofun for discussion.

[Xuanwo]

This issue is stall for a long time and is not actionable. Let's close.