LibCore: Remove main event loop

The main event loop functionality was used in just two places where the
alternative is a bit simpler. Remove it in favor of referencing the
event loop directly, or just invoking `EventLoop::current()`.

Note that we don't need locking in the constructor since we're now only
modifying a thread-local `Vector`. We also don't need locking in the
old call sites to `::with_main_locked()` since we already lock the
event loop in the subsequent `::post_event()` invocation.

0 files changed, 0 insertions, 0 deletions