Record initialization with no designators

[leewei05]

This PR implement record initialization with no designator code generation. Even though we support initializing multiple elements for union, union member access expression will only return the first element (Similar with gcc and clang, they only throw warning)[1].

[1] https://godbolt.org/z/57fYnn95G

[Lai-YT]

I suggest dropping the const specifier for pass-by-value parameters from the function declaration, but keep it in the function definition. This does not apply to const-reference parameters, which should be kept in both places.

Suggested change

	std::size_t offset( // NOLINT(readability-identifier-naming)
	const std::size_t index) const override;
	std::size_t offset( // NOLINT(readability-identifier-naming)
	std::size_t index) const override;

Note that two function declarations differing only in the constness of their pass-by-value parameters are not considered overloads, as they are indistinguishable when called. Removing const from the function declaration is recommended for the following reasons:

1. The caller does not need to know whether the parameter is const or not, as it does not affect the caller. Including const only clutters the function declaration.
2. You might want to change the function's implementation, which could involve removing the const. If const is included in the function declaration, you will have to update it there as well.

[leewei05]

After applying the current fix, compiler will not initialize exceeding elements.

// struct.c 
int main() {
  struct ss;

  struct birth {
    int date;
    int month;
    int year;
  };

  // Compiler will stop initializing elements at index 4 since we only have
  // 3 members defined in `struct birth`.
  struct birth bd1 = {3, 5, 1998, 2000, 2002};

  __builtin_print(bd1.date);

// struct.ssa
function w $main() {
@.start.1
@.body.1
        %.1 =l alloc4 12
        %.2 =w copy 3
        %.3 =l add %.1, 0
        storew %.2, %.3
        %.4 =w copy 5
        %.5 =l add %.1, 4
        storew %.4, %.5
        %.6 =w copy 1998
        %.7 =l add %.1, 8
        storew %.6, %.7
        %.8 =l copy $__builtin_print
        %.9 =w loadw %.1
        %.10 =l add %.1, 0
        %.11 =w loadw %.10
        %.12 =w call $printf(l $__builtin_print_format, w %.11)

[Lai-YT]

Additionally, the NOLINTs can be removed after the renaming.

[Lai-YT]

LGTM! Masterpiece 🤓