CI: skip Ractor test on Windows to avoid job timeout

Gemini said this:

> If a background thread or a Ractor is still "alive" or cleaning up when
> the main test suite finishes, the shell might wait for that process to
> fully relinquish control.

Author: dentarg

spec/addressable/uri_spec.rb

@@ -6821,7 +6821,7 @@ def to_str
     expect(
       Ractor.new { Addressable::URI.parse("http://example.com") }.public_send(value_method)
     ).to eq(main)
-  end
+  end unless (TestHelper.is_mri? && TestHelper.is_windows?) # Since Ruby 4 this test made the Windows job time out
 end
 
 describe Addressable::URI, "when deferring validation" do

spec/spec_helper.rb

@@ -19,11 +19,20 @@
 end if Gem.loaded_specs.key?("simplecov")
 
 class TestHelper
-  def self.native_supported?
-    mri = RUBY_ENGINE == "ruby"
-    windows = RUBY_PLATFORM.include?("mingw")
+  def self.is_jruby?
+    Object.const_defined? :JRUBY_VERSION
+  end
+
+  def self.is_mri?
+    RUBY_ENGINE == "ruby"
+  end
 
-    mri && !windows
+  def self.is_windows?
+    RUBY_DESCRIPTION =~ /mswin|ming|cygwin/
+  end
+
+  def self.native_supported?
+    is_mri? && !is_windows?
   end
 end