It is otherwise impossible to determine which test failed sanitizer/valgrind
check. test/functional/helpers.lua module return was changed so that tests which
do not provide after_each function to get new check will automatically fail.
All syntastic users experienced this problem:
E685: Internal error: get_tv_string_buf()
It's reproducable with:
:call setloclist(0, [''])
So, not given optional arguments to setloclist() lead to some fields not
inizilied and the code took the wrong branches.