Make varray() variadic

[KoBeWi]

Allows to make an array of any size and is probably faster thanks to loop assign instead of appending.

[akien-mga]

Looks great!

I'd suggest rebasing as this is a bit old.

[akien-mga]

Thanks!

[timothyqiu]

Looks similar to this since we have initializer list support in Vector:

#define varray(...) Vector<Variant>({ __VA_ARGS__ })

Update: It compiles and seems to run normally. But compilation fails when I try to use a more simple version Vector<Variant>{ __VA_ARGS__ }. Probably caused by other macro expansions.

[KoBeWi]

Note that would cause

Vector<Variant> v1;
Vector<Variant> v2 = varray(v1);

v2 to be copy of v1 instead of a containing array. I had this problem with #89782

[timothyqiu]

Tested locally and it did not happen. It should not happen either. Constructors with an initializer list argument are preferred over regular ones (the copy constructor in this case).