Remove test TODO comments that have been confirmed by E2E tests

Author: aycabta

test/reline/test_reline.rb

@@ -364,22 +364,10 @@ def test_readline
     assert_include(Reline.private_instance_methods, :readline)
   end
 
-  def test_inner_readline
-    # TODO in Reline::Core
-  end
-
   def test_read_io
     # TODO in Reline::Core
   end
 
-  def test_read_escaped_key
-    # TODO in Reline::Core
-  end
-
-  def test_may_req_ambiguous_char_width
-    # TODO in Reline::Core
-  end
-
   def get_reline_encoding
     if encoding = Reline::IOGate.encoding
       encoding