vinyl: delete run files in single coio call

Currently, vy_run_remove_files calls coio several times under the hood -
once per each run file and data directory. Apart from being inefficient,
this also prevents us from adding some extra logic for thorough file
deletion. So let's perform all the operations in a single coio call.

Needed for tarantool/tarantool-ee#540

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring