[Universal parser] DeVALUE of p->debug_lines and ast->body.script_lines

This patch is part of universal parser work.

## Summary
- Decouple VALUE from members below:
  - `(struct parser_params *)->debug_lines`
  - `(rb_ast_t *)->body.script_lines`
- Instead, they are now `rb_parser_ary_t *`
  - They can also be a `(VALUE)FIXNUM` as before to hold line count
- `ISEQ_BODY(iseq)->variable.script_lines` remains VALUE
  - In order to do this,
  - Add `VALUE script_lines` param to `rb_iseq_new_with_opt()`
  - Introduce `rb_parser_build_script_lines_from()` to convert `rb_parser_ary_t *` into `VALUE`

## Other details
- Extend `rb_parser_ary_t *`. It previously could only store `rb_parser_ast_token *`, now can store script_lines, too
- Change tactics of building the top-level `SCRIPT_LINES__` in `yycompile0()`
  - Before: While parsing, each line of the script is added to `SCRIPT_LINES__[path]`
  - After: After `yyparse(p)`, `SCRIPT_LINES__[path]` will be built from `p->debug_lines`
- Remove the second parameter of `rb_parser_set_script_lines()` to make it simple
- Introduce `script_lines_free()` to be called from `rb_ast_free()` because the GC no longer takes care of the script_lines
- Introduce `rb_parser_string_deep_copy()` in parse.y to maintain script_lines when `rb_ruby_parser_free()` called
  - With regard to this, please see *Future tasks* below

## Future tasks
- Decouple IMEMO from `rb_ast_t *`
  - This lifts the five-members-restriction of Ruby object,
  - So we will be able to move the ownership of the `lex.string_buffer` from parser to AST
  - Then we remove `rb_parser_string_deep_copy()` to make the whole thing simple

vm_eval.c

@@ -1809,7 +1809,7 @@ eval_make_iseq(VALUE src, VALUE fname, int line,
     }
 
     rb_parser_set_context(parser, parent, FALSE);
-    rb_parser_set_script_lines(parser, RBOOL(ruby_vm_keep_script_lines));
+    if (ruby_vm_keep_script_lines) rb_parser_set_script_lines(parser);
     ast = rb_parser_compile_string_path(parser, fname, src, line);
     if (ast->body.root) {
         ast->body.coverage_enabled = coverage_enabled;