They are now called "utility functions" to avoid confusion with methods
of builtin types, and be consistent with the naming in Variant.
Core utility functions are now available in GDScript. The ones missing
in core are added specifically to GDScript as helpers for convenience.
Some functions were remove when there are better ways to do, reducing
redundancy and cleaning up the global scope.
Almost all instructions need variant arguments. With this change they
are loaded in an array before each instruction call. This makes the
addressing code be localized to less places, improving compilation
overhead and binary size by a small margin.
This should not affect performance.
