Ruby Head compatibility

I'm actively experimenting with the head Ruby builds (mostly due to #555) and collecting some compatibility
issues compared to 3.3 release here.

Gem/lib versions:

• ruby_wasm: 2.7.0
• js: 2.7.0

• Tempfile vs. /dev/null: https://github.com/ruby/tempfile/pull/38

This commit broke loading tempfile.rb: https://github.com/ruby/ruby/commit/136cbf04419acf993357701e54712f921a294355

require "tempfile"

# => 'File#initialize': No such file or directory @ rb_sysopen - /dev/null (Errno::ENOENT)

Not sure how to properly handle /dev/null in Wasm, though; maybe, we should return nil for IO::NULL and check for nil-ness whenever it's used 🤔

• Fails to require digest/sha1: https://github.com/ruby/digest/pull/71

require "digest/sha1"

#=> <internal:/usr/local/lib/ruby/3.4.0+0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require': rb_digest_wrap_metadata not found (LoadError)
<internal:/usr/local/lib/ruby/3.4.0+0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require'
eval:3:in '<main>'
-e:in 'Kernel.eval'

Worked fine in 3.3.

Reproduisez les deux échecs avec ruby.wasm 2.7.0, en commençant par les exemples de require pour tempfile.rb et digest/sha1. Examinez les pull requests référencées concernant tempfile et digest ainsi que le commit de Ruby, puis comparez le comportement avec Ruby 3.3. Le travail est terminé lorsque les deux bibliothèques se chargent correctement dans le build WebAssembly de la tête.