runtime: drop basic scheduler tasks inside context

[Darksonn]

Closes: #3963
Closes: #3966

[Darksonn]

The test failure appears to be due to this test:

tokio/tokio/tests/rt_common.rs

Lines 886 to 908 in 09b770c

	// This test is currently ignored on Windows because of a
	// rust-lang issue in thread local storage destructors.
	// See https://github.com/rust-lang/rust/issues/74875
	#[test]
	#[cfg(not(windows))]
	fn runtime_in_thread_local() {
	use std::cell::RefCell;
	use std::thread;
	thread_local!(
	static R: RefCell<Option<Runtime>> = RefCell::new(None);
	);
	thread::spawn(|| {
	R.with(|cell| {
	let rt = rt();
	let rt = Arc::try_unwrap(rt).unwrap();
	*cell.borrow_mut() = Some(rt);
	});
	let _rt = rt();
	}).join().unwrap();
	}

It fails with cannot access a Thread Local Storage value during or after destruction: AccessError inside the set_context_guard call.

Ideas?

[carllerche]

It seems like we need to replace our usage of with -> try_with and gracefully handle the error case.

[carllerche]

The change itself seems fine, I'll +1 once CI passes.