Ruby

test_signal.rb: use assert_in_out_err

• test/ruby/test_signal.rb (test_kill_immediately_before_termination):
  use assert_in_out_err instead of separated fork and assert.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41416 b2dd03c8-39d4-4d8f-98ff-823fe69b080e