Add `bin/mrbc --no-ext-ops` switch

Print error before cleanup in `codegen_error()`

Previously, it always pointed to the highest scope as the location of the error.

  - example code `code.rb`

    ```ruby
    huge_num = "1" + "0" * 300; eval <<CODE, nil, "test.rb", 1
    class Object
      module A
        #{huge_num}
      end
    end
    CODE
    ```

  - Before this patch

    ```console
    % bin/mruby code.rb
    test.rb:1: integer too big
    trace (most recent call last):
            [1] code.rb:1
    code.rb:1:in eval: codegen error (ScriptError)
    ```

  - After this patch

    ```console
    % bin/mruby code.rb
    test.rb:3: integer too big
    trace (most recent call last):
            [1] code.rb:1
    code.rb:1:in eval: codegen error (ScriptError)
    ```

Print an error if `OP_EXT[123]` is needed when generating mruby binary.
This may be useful for mruby/c.

Inspired by #5590.

build(deps): bump actions/upload-artifact from 2.2.4 to 2.3.1

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 2.2.4 to 2.3.1.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](https://github.com/actions/upload-artifact/compare/v2.2.4...v2.3.1)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-type: direct:production
  update-type: version-update:semver-minor
...
Signed-off-by: dependabot[bot] <support@github.com>

Ref #5597

Avoid losing the upper digits for mruby binary

The function may invoke the garbage collection and it requires
`mrb_state` to run.

- `rlen` keeps 16 bits.
- `ilen` keeps 32 bits.

Note that this change will break mruby binary format compatibility.

With some refactoring.

* `ret` argument is always non-nil, so no check needed.
* move allocation check right after malloc().
* simplify conditions.

The existence of this member reduces memory and execution time.

Add `Array#{repeated_combination,repeated_permutation}` methods

Ruby 1.9.2 feature.

ref: https://docs.ruby-lang.org/ja/3.1.0/method/Array/i/repeated_combination.html
ref: https://docs.ruby-lang.org/ja/3.1.0/method/Array/i/repeated_permutation.html

fix #5593

It used to return wrong value for 14 positional arguments.

Now `iv_get()` returns `pos+1` if it finds the entry, so you don't need
to call `iv_put()`. You can replace the entry value by assigning to
`t->ptr[pos-1]`.

Class variables are slower than instance variables of classes.

Instead embed deleted flag in the key (`mrb_sym` only occupies 30bits).

`iv_size()` is approximated by the allocated table size.

As a general principles numeric instructions should not be prefixed by
`OP_EXT` instructions since they are not supported by "mruby/c".

This is a fundamentally simplified reimplementation of #5317
by @shuujii

Instead of having array of `struct iv_elem`, we have sequences of keys
and values packed in single chunk of malloc'ed memory. We don't have to
worry about gaps from alignment, especially on 64 bit architecture,
where `sizeof(struct iv_elem)` probably consumes 16 bytes, but
`sizeof(mrb_sym)+sizeof(mrb_value)` is 12 bytes.

In addition, this change could improve memory access locality.

close #5317