test_filehandler.rb: reap zombie

* test/webrick/test_filehandler.rb (test_short_filename): use backtick
  to reap zombie, instead of leaving opened stream after reading.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41524 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
test_filehandler.rb: fix for non-NTFS

* test/webrick/test_filehandler.rb (test_script_disclosure): Alternate
  Data Stream is available only on NTFS.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41525 b2dd03c8-39d4-4d8f-98ff-823fe69b080e