remove hacks preventing jruby from using racc and rexical

modern versions of both run fine on jruby, so as dev tools this is
fine.

also update parser.rb with output from modern racc.

Gemfile

@@ -14,8 +14,8 @@ gem "minitest", "~>5.8.4", :group => [:development, :test]
 gem "rake", "~>12.0", :group => [:development, :test]
 gem "rake-compiler", "~>1.0.3", :group => [:development, :test]
 gem "rake-compiler-dock", "~>0.6.2", :group => [:development, :test]
-gem "racc", "~>1.4.14", :group => [:development, :test], :platform => [:ruby, :mingw, :x64_mingw]
-gem "rexical", "~>1.0.5", :group => [:development, :test], :platform => [:ruby, :mingw, :x64_mingw]
+gem "racc", "~>1.4.14", :group => [:development, :test]
+gem "rexical", "~>1.0.5", :group => [:development, :test]
 gem "concourse", "~>0.15", :group => [:development, :test]
 gem "rdoc", ">=4.0", "<7", :group => [:development, :test]
 gem "hoe", "~>3.17", :group => [:development, :test]

Rakefile

@@ -250,42 +250,17 @@ end
 desc "Generate css/parser.rb and css/tokenizer.rex"
 task 'generate' => [GENERATED_PARSER, GENERATED_TOKENIZER]
 task 'gem:spec' => 'generate' if Rake::Task.task_defined?("gem:spec")
-
-# This is a big hack to make sure that the racc and rexical
-# dependencies in the Gemfile are constrainted to ruby platforms
-# (i.e. MRI and Rubinius). There's no way to do that through hoe,
-# and any solution will require changing hoe and hoe-bundler.
-old_gemfile_task = Rake::Task['bundler:gemfile'] rescue nil
-task 'bundler:gemfile' do
-  old_gemfile_task.invoke if old_gemfile_task
-
-  lines = File.open('Gemfile', 'r') { |f| f.readlines }.map do |line|
-    line =~ /racc|rexical/ ? "#{line.strip}, :platform => [:ruby, :mingw, :x64_mingw]" : line
-  end
-  File.open('Gemfile', 'w') { |f| lines.each { |line| f.puts line } }
+[:compile, :check_manifest].each do |task_name|
+  Rake::Task[task_name].prerequisites << GENERATED_PARSER
+  Rake::Task[task_name].prerequisites << GENERATED_TOKENIZER
 end
 
 file GENERATED_PARSER => "lib/nokogiri/css/parser.y" do |t|
-  if java?
-    warn "WARNING: #{GENERATED_PARSER} may be out of date:"
-    sh "ls -lt #{t.name} #{t.prerequisites.first}"
-  else
-    sh "racc -l -o #{t.name} #{t.prerequisites.first}"
-  end
+  sh "racc -l -o #{t.name} #{t.prerequisites.first}"
 end
 
 file GENERATED_TOKENIZER => "lib/nokogiri/css/tokenizer.rex" do |t|
-  if java?
-    warn "WARNING: #{GENERATED_TOKENIZER} may be out of date:"
-    sh "ls -lt #{t.name} #{t.prerequisites.first}"
-  else
-    sh "rex --independent -o #{t.name} #{t.prerequisites.first}"
-  end
-end
-
-[:compile, :check_manifest].each do |task_name|
-  Rake::Task[task_name].prerequisites << GENERATED_PARSER
-  Rake::Task[task_name].prerequisites << GENERATED_TOKENIZER
+  sh "rex --independent -o #{t.name} #{t.prerequisites.first}"
 end
 
 # ----------------------------------------