Fix memory leak in complemented method entries

    [Bug #19894]

    When a copy of a complemented method entry is created, there are two
    issues:

    1. IMEMO_FL_USER3 is not copied, so the complemented status is not
       copied over.
    2. In rb_method_entry_clone we increment both alias_count and
       complemented_count. However, when we free the method entry in
       rb_method_definition_release, we only decrement one of the two
       counters, resulting in the rb_method_definition_t being leaked.

Co-authored-by: Adam Hess <adamhess1991@gmail.com>
    ---
     method.h                 |  5 +++--
     test/ruby/test_module.rb | 29 +++++++++++++++++++++++++++++
     vm_method.c              |  8 +++++---
     3 files changed, 37 insertions(+), 5 deletions(-)