* eval: fix assertion failure in garbage collection
fixes#12387, #12430
Lists with CopyID+1 linked only from previous_funccal may be removed in
the garbage collection. Therefore, the terms of the assertions are not
correct. This can be confirmed by the following (The l:x with CopyID+1 of
the first function call needs to be removed by garbage collection):
func! s:f()
let l:x = [1]
let g:x = l:
endfunc
for _ in range(2)
call s:f()
endfor
call garbagecollect()
" press any key
* test: add test for #12387, #12430
21453e8f09