Ruby

[rubygems/rubygems] Fix gem update --system crash while regenerating binstubs

Since a few commits ago, we no longer call Gem::Specification.reset
after each invocation of Gem::Installer#install. This means we don't
call it when the default Bundler is installed during gem update --system. This causes no issues until the end of the upgrade process
when:

• The previous default Bundler spec is removed from disk.

• All specification stubs are turned into real specifications by loading
  them from disk. But the one for Bundler no longer exists so
  materializes to nil and regenerating binstubs crashes like this:

  Bundler 2.4.0.dev installed
  RubyGems 3.4.0.dev installed
  Regenerating binstubs
  ERROR:  While executing gem ... (NoMethodError)
      undefined method `platform' for nil:NilClass
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/commands/pristine_command.rb:116:in `block in execute'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/specification.rb:981:in `block in each'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/specification.rb:980:in `each'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/specification.rb:980:in `each'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/commands/pristine_command.rb:116:in `map'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/commands/pristine_command.rb:116:in `each'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/commands/pristine_command.rb:116:in `select'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/commands/pristine_command.rb:116:in `execute'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/command.rb:323:in `invoke_with_build_args'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/command.rb:301:in `invoke'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/commands/setup_command.rb:604:in `regenerate_binstubs'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/commands/setup_command.rb:183:in `execute'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/command.rb:323:in `invoke_with_build_args'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/command_manager.rb:185:in `process_args'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/command_manager.rb:149:in `run'
    /Users/deivid/Code/rubygems/rubygems/lib/rubygems/gem_runner.rb:51:in `run'
  setup.rb:33:in `<main>'
  

We fix it by more carefully managing the removal of the previous default
Bundler gem.

https://github.com/rubygems/rubygems/commit/9989f6d5af