_ebpf_link_instance_invoke_batch_begin and _ebpf_link_instance_invoke_batch_end use the expensive EX_RUNDOWN_REF construct.

Given that this block of code is already protected by epoch_enter/epoch_exit, the code should rely on epoch protection to detect when the last program using a program information has exited.

Proposed changes:

1. In _ebpf_program_type_specific_program_information_detach_provider set program->extension_program_data to NULL, then call ebpf_epoch_synchronize.
2. In ebpf_program_invoke check if extension_program_data is NULL and fail the invoke.
3. Remove rundown protection from batch_begin/batch_end.

This will achieve two things:

1. Speed up batch begin/end.
2. Allow batch across different programs.