In TaskQueue::take_tasks_matching(), we were not discarding tasks for
destroyed documents as we now do in ::take_first_runnable() since commit
c8baa6e179.
This fixes some occurrences of missing browsing contexts / active
documents in TraversableNavigable::destroy_top_level_traversable().
Previously, destroyed-document tasks were forced to be runnable to
prevent them from leaking in the task queue. Instead, discard them
during task selection so their callbacks never run with stale state.
This used to cause issues with a couple of `spin_until()`s in the past,
but since we've removed some of them that had to do with the document
lifecycle, let's see if we can stick closer to the spec now.
Note that it's not actually executing tasks in parallel, it's still
throwing them on the HTML event loop task queue, each with its own
unique task source.
This makes our fetch implementation a lot more robust when HTTP caching
is enabled, and you can now click links on https://terminal.shop/
without hitting TODO assertions in fetch.
Before this change, tasks associated with a destroyed document would get
stuck in the task queue forever, since document-associated tasks are not
allowed to run when their document isn't fully active (and destroyed
documents never become fully active again). This caused everything
captured by task callbacks to leak.
We now treat tasks for destroyed documents as runnable immediately,
which gets them out of the queue.
This fixes another massive GC leak on Speedometer.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
Now that the heap has no knowledge about a JavaScript realm and is
purely for managing the memory of the heap, it does not make sense
to name this function to say that it is a non-realm variant.
