Adapt new way of NeoVM tests delivering #3204
Description
Is your feature request related to a problem? Please describe.
Since neo-project/neo#2970 NeoVM tests are located in the https://github.com/neo-project/neo, so we need to change our VM tests submodule approach to downloading/updating script.
Describe the solution you'd like
A script to download the tests folder and to update it later. From the first glance, it may be helpful to try out the https://git-scm.com/docs/git-sparse-checkout.