I think that they have to add a native like this to SourceMod.
Well I can tell you this post is really unnecessary as:
This stock has already been posted on the forum several times.
They probably wont be adding it as a native to core Sourcemod as simply just killing a timer and stating it as INVALID_HANDLE is all this stock does. (Read from older thread(s))
This has probably been used in several includes already.