Fix debug location for ~check_proc_is_not_closure

[HertzDevil]

When passing a closure to a lib fun and the compiler cannot figure this out, the program calls ~check_proc_is_not_closure to raise an exception. This generated LLVM function has a proper debug location, but the inner raise call doesn't, and is still attached to the beginning of the source file:

Here the filtered assembly output on Compiler Explorer shows the isolated raise call because of this. This PR fixes that.

[asterite]

Could we maybe change the location of the call (maybe not caching it, or changing it on every use) so it points to the correct location? That said, I'm not sure what would be better this way.

[HertzDevil]

That would probably be the same as inlining ~check_proc_is_not_closure in every place that needs it (passing Procs to lib funs, as well as assigning Procs to members of lib or extern structs).

[straight-shoota]

This patch looks good. If we can make it even better, I'm all in.