Remove some unsafes by using atomics

[WorldSEnder]

Description

Removes some uses of unsafe operations by substituting them with atomic operations. These are, due to the single-threaded nature of the current wasm target, lowered to normal operations on simple datatypes, as far as I know.

Uses Ordering::Relaxed since none of the operations are used as synchronization primitives.

Checklist

• I have run cargo make pr-flow
• I have reviewed my own code

[ranile]

Web Assembly is going to support threads and atomics (see proposal). I'm not sure if this is a good solution to avoiding unsafe as atomics do come with a cost. I think safety comments are fine with unsafe blocks. If we really want to avoid unsafe, thread_locals would be a better solution

[WorldSEnder]

A shame that the proposal includes only sequential consistency instructions, which makes Ordering::Relaxed pointless. With a good implementation, that should have almost no cost for a boolean that is rarely modified. I'd be down for revisiting this when the proposal moves ahead?

thread_locals are hard to set globally in set_event_bubbling.

[ranile]

I don't have a strict opinion on it. If it doesn't degrade the performance, I'm fine with keeping the atomics

[voidpumpkin]

Blocked due to benchmarks not working atm

[voidpumpkin]

@WorldSEnder could you rebase? Benchmarks are fixed but it will end up comparing older yew with master

[WorldSEnder]

@voidpumpkin Done. The Benchmark check has successfully built, where can I see the results though? 😄

[ranile]

@WorldSEnder benchmark results can be found here: https://github.com/yewstack/yew/runs/4659120701?check_suite_focus=true#step:15:24

I agree that we should make them more visible. I had to dig through the logs to find them

[voidpumpkin]

04_select1k seems to be scuffed and shows performance decreases even when there are no changes.
03_update10th1k_x16 seems like it was a performance increase.
everything else stayed marginal
Though idk how much we can trust those benchmarks. For this PR it is enough though.