Deno: various async fs ops are not actually async

[ry]

Example op_fdatasync_async

https://github.com/denoland/deno/blob/11afd071aec2d5ea6eb37a934c0835d8f6b1e764/cli/ops/fs.rs#L285-L300

This ought to be calling tokio::task::spawn_blocking.

op_stat_async is properly implemented
https://github.com/denoland/deno/blob/11afd071aec2d5ea6eb37a934c0835d8f6b1e764/cli/ops/fs.rs#L864-L886

[caspervonb]

This ought to be calling tokio::task::spawn_blocking.

Hmm I know I made them fake async (as in, not calling tokio::fs variants which are available) but this looks unfamiliar 🤔
Do we want to just go for spawn_blocking here or all the way async?

These used to be blocking_json; I'll rewrite them as tokio::fs::File async calls.

[caspervonb]

Bit of churn recently in ops; I'll revisit once the interface has been the same for a couple of days in a row 😉

[wperron]

I can take a crack at this one

yeah as Casper said, I don't think this is really a "good first issue", clearly out of my comfort zone for now, if anyone else wants to take it 👍

[caspervonb]

Non trivial to fix at the moment until resource locks are sorted out.