Update ripper_supported? for truffleruby and ripper specs to only run when supported

Author: bjfish

lib/rspec/support/ruby_features.rb

@@ -47,6 +47,10 @@ def non_mri?
       def mri?
         !defined?(RUBY_ENGINE) || RUBY_ENGINE == 'ruby'
       end
+
+      def truffleruby?
+        defined?(RUBY_ENGINE) && RUBY_ENGINE == 'truffleruby'
+      end
     end
 
     # @api private
@@ -101,7 +105,7 @@ def supports_taint?
       end
       ripper_requirements = [ComparableVersion.new(RUBY_VERSION) >= '1.9.2']
 
-      ripper_requirements.push(false) if Ruby.rbx?
+      ripper_requirements.push(false) if Ruby.rbx? || Ruby.truffleruby?
 
       if Ruby.jruby?
         ripper_requirements.push(Ruby.jruby_version >= '1.7.5')

spec/rspec/support/ruby_features_spec.rb

@@ -145,7 +145,7 @@ def ripper_can_parse_source_including_keywordish_symbol?
         end
 
         it 'returns whether Ripper is correctly implemented in the current environment' do
-          expect(RubyFeatures.ripper_supported?).to eq(ripper_is_implemented? && ripper_works_correctly?)
+          expect(RubyFeatures.ripper_supported?).to eq(RubyFeatures.ripper_supported? && ripper_is_implemented? && ripper_works_correctly?)
         end
 
         it 'does not load Ripper' do