Fix mesecons displayed as unknown(??) mod in the profiler

[zmv7]

Currently there is the replacement of existing globalstep function, but it doesn't consider callback origins, therefore, the engine doesn't know what mod is the owner of the new function. The result - there is unknown entry in the profiler output, displayed as ?? modname with * instrumentation.

This patch fixes it by setting callback origin of the replaced globalstep function

[SmallJoker]

Yes. LGTM.
If you wanted to optimize it even further, minetest.after might be an option to delay the globalstep registration. But then again, you'd also have to assign the function origin once.

[zmv7]

Yes. LGTM. If you wanted to optimize it even further, minetest.after might be an option to delay the globalstep registration. But then again, you'd also have to assign the function origin once.

Callbacks registered using minetest.after also displayed as ?? unfortunately

[SmallJoker]

@zmv7 Hence the 2nd sentence, by which I was referring to minetest.callback_origins.