fix(core): keep event loop alive if there are ticks scheduled

[bnoordhuis]

Demonstrates that nextTick() callbacks aren't invoked when there isn't
anything else keeping the event loop alive. Specifically:

1. nextTickCallback is invoked, but
2. macrotaskCallback is not

[bnoordhuis]

The test is passing after the second commit but I'm sorta confused: the "has tick scheduled" flag is still true but the event loop exits because the macrotask callback says it's done. Is that expected behavior?

[bartlomieju]

The test is passing after the second commit but I'm sorta confused: the "has tick scheduled" flag is still true but the event loop exits because the macrotask callback says it's done. Is that expected behavior?

I forgot to account for next ticks in keeping event loop alive. We should add an additional check here:

deno/core/runtime.rs

Lines 804 to 822 in c82ce74

	let has_pending_ops = !state.pending_ops.is_empty();
	let has_pending_dyn_imports = module_map.has_pending_dynamic_imports();
	let has_pending_dyn_module_evaluation =
	!state.pending_dyn_mod_evaluate.is_empty();
	let has_pending_module_evaluation = state.pending_mod_evaluate.is_some();
	let has_pending_background_tasks =
	self.v8_isolate().has_pending_background_tasks();
	let inspector_has_active_sessions = self
	.inspector
	.as_ref()
	.map(|i| i.has_active_sessions())
	.unwrap_or(false);
	if !has_pending_ops
	&& !has_pending_dyn_imports
	&& !has_pending_dyn_module_evaluation
	&& !has_pending_module_evaluation
	&& !has_pending_background_tasks

and keep event loop running

[bartlomieju]

@bnoordhuis PTAL

[bnoordhuis]

LGTM but I can't approve my own PRs. =)