I don't know that JIT compiling, or interpretive runtimes will be introduced by Microsoft or not. I really haven't heard anything about that.
That being said, there is nothing to stop a 3rd party developer from releasing something as part of a Windows Store app that will run in its own environment, and do exactly what you are looking for, or maybe something similar yet not what you're looking for.
There are examples in the store already.
https://forums.windowscentral.com/e?...token=1DJB8QdV https://forums.windowscentral.com/e?...token=MYc5LHnR https://forums.windowscentral.com/e?...token=puXDuK7S https://forums.windowscentral.com/e?...token=qhS_nln1 https://forums.windowscentral.com/e?...token=KxiuDz-l https://forums.windowscentral.com/e?...token=h9ftTOUD
I'm not sure how compatible they are with Windows 10 Mobile, as they were already in the store before Windows 10 Mobile was introduced.