test_process.rb: test if success?

* test/ruby/test_process.rb (test_rlimit_value): should not use
  magic number 0, which may not be EXIT_SUCCESS.  use `success?`
  instead.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45477 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_process.rb

@@ -131,7 +131,7 @@ class TestProcess < Test::Unit::TestCase
           exit false
         end
       End
-      assert_not_equal(0, s.exitstatus)
+      assert_not_predicate(s, :success?)
       s = run_in_child(<<-'End')
         cur, max = Process.getrlimit(:NOFILE)
         Process.setrlimit(:NOFILE, [max-10, cur].min)
@@ -141,7 +141,7 @@ class TestProcess < Test::Unit::TestCase
           exit false
         end
       End
-      assert_not_equal(0, s.exitstatus)
+      assert_not_predicate(s, :success?)
     end
   end