When the global timer fires earlier than expected, which apparently
happens sometimes on server editions of Windows, we didn't call any
setTimeout callbacks, but we *also* didn't reschedule the global timer
to fire again later.

When this situation occurred it would make deno exit abruptly if there
were no other asynchronous ops running on the event loop. It could also
lead to application hangs if the upcoming setTimeout callback was
critical for the application to make progress.

* Revert "port more ops to JSON (#2809)"

This reverts commit 137f3373.

* Revert "port ops to JSON: compiler, errors, fetch, files (#2804)"

This reverts commit 79f82cf1.

* Revert "Port rest of os ops to JSON (#2802)"

This reverts commit 5b2baa5c.

Just some clean up reorganization around flatbuffer/minimal dispatch
code. This is prep for adding a JSON dispatcher.

Note cli/dispatch_minimal.rs ops are not yet included in cli/ops.

This is part of work towards #2730