revert revert of r65285

because CI was actually hitting another one.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65291 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/-ext-/thread_fd_close/test_thread_fd_close.rb

@@ -6,8 +6,6 @@ require 'io/wait'
 class TestThreadFdClose < Test::Unit::TestCase
 
   def test_thread_fd_close
-    skip "MJIT thread is unexpected for this" if RubyVM::MJIT.enabled?
-
     IO.pipe do |r, w|
       th = Thread.new do
         begin

test/rubygems/test_gem_util.rb

@@ -5,7 +5,6 @@ require 'rubygems/util'
 class TestGemUtil < Gem::TestCase
 
   def test_class_popen
-    skip "MJIT executes process and it's caught by Process.wait(-1)" if defined?(RubyVM::MJIT) && RubyVM::MJIT.enabled?
     assert_equal "0\n", Gem::Util.popen(Gem.ruby, '-e', 'p 0')
 
     assert_raises Errno::ECHILD do