Rename TestScheduler* to TestFiber for convention of the test directory

test/fiber/test_enumerator.rb

@@ -3,7 +3,7 @@ require 'test/unit'
 require 'socket'
 require_relative 'scheduler'
 
-class TestSchedulerEnumerator < Test::Unit::TestCase
+class TestFiberEnumerator < Test::Unit::TestCase
   MESSAGE = "Hello World"
 
   def test_read_characters

test/fiber/test_http.rb

@@ -7,7 +7,7 @@ require 'openssl'
 require 'test/unit'
 require_relative 'scheduler'
 
-class TestSchedulerHTTP < Test::Unit::TestCase
+class TestFiberHTTP < Test::Unit::TestCase
   def test_get
     Thread.new do
       scheduler = Scheduler.new

test/fiber/test_io.rb

@@ -2,7 +2,7 @@
 require 'test/unit'
 require_relative 'scheduler'
 
-class TestSchedulerIO < Test::Unit::TestCase
+class TestFiberIO < Test::Unit::TestCase
   MESSAGE = "Hello World"
 
   def test_read

test/fiber/test_mutex.rb

@@ -2,7 +2,7 @@
 require 'test/unit'
 require_relative 'scheduler'
 
-class TestSchedulerMutex < Test::Unit::TestCase
+class TestFiberMutex < Test::Unit::TestCase
   def test_mutex_synchronize
     mutex = Mutex.new
 

test/fiber/test_scheduler.rb

@@ -2,7 +2,7 @@
 require 'test/unit'
 require_relative 'scheduler'
 
-class TestSchedulerFiber < Test::Unit::TestCase
+class TestFiberScheduler < Test::Unit::TestCase
   def test_fiber_without_scheduler
     # Cannot create fiber without scheduler.
     assert_raise RuntimeError do

test/fiber/test_sleep.rb

@@ -2,7 +2,7 @@
 require 'test/unit'
 require_relative 'scheduler'
 
-class TestSchedulerSleep < Test::Unit::TestCase
+class TestFiberSleep < Test::Unit::TestCase
   ITEMS = [0, 1, 2, 3, 4]
 
   def test_sleep