Cleanup diff against upstream. Add comments

I did a `git diff --stat` against upstream and looked at all the files
that are outside of YJIT to come up with these minor changes.

1 files changed, 0 insertions, 2 deletions

diff --git a/iseq.h b/iseq.h
index 9d8735bad1..8387f90e9a 100644
--- a/iseq.h
+++ b/iseq.h
@@ -315,8 +315,6 @@ VALUE rb_iseq_defined_string(enum defined_type type);
 /* vm.c */
 VALUE rb_iseq_local_variables(const rb_iseq_t *iseq);
 
-NOINLINE(void rb_yjit_empty_func_with_ec(rb_control_frame_t *cfp, rb_execution_context_t *ec));
-
 RUBY_SYMBOL_EXPORT_END
 
 #endif /* RUBY_ISEQ_H */