fix(core): pump event loop during module loading to prevent hook deadlock
When module.register() activates load hooks, subsequent module loading
via load_main_es_module/load_side_es_module would deadlock because the
Rust module loader pushes load requests to a queue that requires the
JS event loop to process (via op_module_hooks_poll_load), but the
event loop wasn't running during module loading.
Fix by interleaving event loop ticks with module load polling in
load_main_es_module and load_side_es_module. Uses raw isolate pointers
(same pattern as poll_event_loop) to avoid borrow conflicts between
the module load future and the event loop pump.