fix: array var-args decay to pointers

[mhasel]

Unsized variadic arguments of type STRING and ARRAY now decay to pointers of the underlying type as per the C specification.

Where previously we had to explicitly call REF or ADR, e.g.
printf('String: %s', REF(myString));
which would result in
%call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([11 x i8], [11 x i8]* @utf08_literal_0, i32 0, i32 0), [81 x i8]* %myString)
we can now just pass the string directly:
printf('String: %s',myString);

%2 = bitcast [81 x i8]* %myString to i8*
%call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([11 x i8], [11 x i8]* @utf08_literal_0, i32 0, i32 0), i8* %2)

Interestingly enough, since we previously passed a pointer to an array when calling REF, this is not a breaking change. Both approaches work, at least for printf.