Skip EBADF spec in MJIT test for now

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67348 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

spec/ruby/core/file/open_spec.rb

@@ -165,6 +165,7 @@ describe "File.open" do
     File.exist?(@file).should == true
   end
 
+  without_feature :mjit do # [ruby-core:90895] MJIT worker may leave fd open in a forked child. TODO: consider acquiring GVL from MJIT worker.
     it "opens a file with a file descriptor d and a block" do
       @fh = File.open(@file)
       @fh.should be_kind_of(File)
@@ -179,6 +180,7 @@ describe "File.open" do
 
       File.exist?(@file).should == true
     end
+  end
 
   it "opens a file that no exists when use File::WRONLY mode" do
     lambda { File.open(@nonexistent, File::WRONLY) }.should raise_error(Errno::ENOENT)