kx.coroutines: migrate to the new memory model

[petertrr]

Now we are using version -native-mt of kx.coroutines. It will be discontinued soon-ish, so we may start adopting the new MM. It has already been done in save-agent in https://github.com/saveourtool/save-cloud/commit/8d1e00644a435ca680f840d7efc3fbcbf73501d4, so it can be used as a reference for save-cli too.