test_fiber.rb: fix test_create_fiber_in_new_thread

* test/ruby/test_fiber.rb (test_create_fiber_in_new_thread):
  prefix to run, and get the result value not only waiting.
  [Bug #14642]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63081 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_fiber.rb

@@ -379,12 +379,12 @@ class TestFiber < Test::Unit::TestCase
     assert_match(/resumed/, Fiber.current.to_s)
   end
 
-  def assert_create_fiber_in_new_thread
+  def test_create_fiber_in_new_thread
     ret = Thread.new{
       Thread.new{
         Fiber.new{Fiber.yield :ok}.resume
-      }.join
-    }.join
+      }.value
+    }.value
     assert_equal :ok, ret, '[Bug #14642]'
   end
 end