Use vendored performance API to handle timing on WASM

[9SMTM6]

Before that this used wasm_timer, but only for Instant::now. But that panicked on web_workers, because it got there by going over the window, which isn't present in web workers.

This still doesn't work on all browsers though because of browser bugs, thus I added an assertion against usage on web-workers, that can be disabled if one so chooses.

This still needs documentation updates and a bit more testing to be done, but before that I wanted to discuss the implementation. Thus a draft PR.

See #3313.

[9SMTM6]

Note that this code, other than I expected (or at least hoped) still doesnt work on Windows, where performance.now isn't broken, which means theres still other things not working as expected.

@Dirbaio Note how I had to wrap the check for whether we're in a webworker into thread_local. I am wondering why the general static in time_driver_impl isn't in thread local storage. That's the one thing I can think of as potential issue right now. But then, would that not potentially be an issue elsewhere? And changing this, without branching the macro, would influence change other implementations.

Note I did of course try to comment out the executor on the main thread, to see if then the executor on the webworker would work fine, and it was still stuck.

If you don't think this is the issue, I don't know what else to try. As it stands this PR only fixes a panic where the remainder doesn't work anyways, and potentially (but not certainly) makes a complete fix easier for someone else, so I don't know if merging this is worth it.

If you think its worth it, I will add documentation of this particular issue and that there seem to be other issues, otherwise feel free to close this.