[rubygems/rubygems] Remove no longer needed fiddle hacks

RubyInstaller has released patch versions backporting their changes to
not load `fiddle` on boot, so all these are no longer necessary.

https://github.com/rubygems/rubygems/commit/05a307deb2

spec/bundler/commands/clean_spec.rb

@@ -638,11 +638,6 @@ RSpec.describe "bundle clean" do
       s.executables = "irb"
     end
 
-    if Gem.win_platform? && RUBY_VERSION < "3.1.0"
-      default_fiddle_version = ruby "require 'fiddle'; puts Gem.loaded_specs['fiddle'].version"
-      realworld_system_gems "fiddle --version #{default_fiddle_version}"
-    end
-
     realworld_system_gems "tsort --version 0.1.0", "pathname --version 0.1.0", "set --version 1.0.1"
 
     install_gemfile <<-G

spec/bundler/install/gems/standalone_spec.rb

@@ -128,11 +128,6 @@ RSpec.shared_examples "bundle install --standalone" do
       skip "does not work on rubygems versions where `--install_dir` doesn't respect --default" unless Gem::Installer.for_spec(loaded_gemspec, :install_dir => "/foo").default_spec_file == "/foo/specifications/default/bundler-#{Bundler::VERSION}.gemspec" # Since rubygems 3.2.0.rc.2
       skip "does not work on old rubies because the realworld gems that need to be installed don't support them" if RUBY_VERSION < "2.7.0"
 
-      if Gem.win_platform? && RUBY_VERSION < "3.1.0"
-        default_fiddle_version = ruby "require 'fiddle'; puts Gem.loaded_specs['fiddle'].version"
-        realworld_system_gems "fiddle --version #{default_fiddle_version}"
-      end
-
       realworld_system_gems "tsort --version 0.1.0"
 
       necessary_system_gems = ["optparse --version 0.1.1", "psych --version 3.3.2", "logger --version 1.4.3", "etc --version 1.2.0", "stringio --version 3.0.1"]

spec/bundler/runtime/inline_spec.rb

@@ -449,8 +449,6 @@ RSpec.describe "bundler/inline#gemfile" do
 
     realworld_system_gems "pathname --version 0.2.0"
 
-    realworld_system_gems "fiddle" # not sure why, but this is needed on Windows to boot rubygems successfully
-
     realworld_system_gems "timeout uri" # this spec uses net/http which requires these default gems
 
     script <<-RUBY, :dir => tmp("path_without_gemfile"), :env => { "BUNDLER_GEM_DEFAULT_DIR" => system_gem_path.to_s }

spec/bundler/runtime/setup_spec.rb

@@ -1309,7 +1309,6 @@ end
         else
           %w[io-console openssl]
         end << "bundler"
-        exempts << "fiddle" if Gem.win_platform? && Gem.rubygems_version >= Gem::Version.new("2.7")
         exempts << "uri" if Gem.ruby_version >= Gem::Version.new("2.7")
         exempts << "pathname" if Gem.ruby_version >= Gem::Version.new("3.0")
         exempts << "set" unless Gem.rubygems_version >= Gem::Version.new("3.2.6")