test_yamatanooroti: codepage on legacy conhost even if only display DBCS chars

test_yamatanooroti: change console condepage on legacy conhost even if only display DBCS characters (no input DBCS)
omit if changing codepage failed
writing DBCS characters to legacy console displays '?' character. confirmed on Windows 11 dev VM (that has no codepage 932 on legacy mode enabled conhost)

Author: YO4

test/reline/yamatanooroti/test_rendering.rb

@@ -1220,7 +1220,12 @@ def test_simple_dialog_scrollbar_with_moving_to_left
 
     def test_dialog_with_fullwidth_chars
       ENV['RELINE_TEST_PROMPT'] = '> '
-      start_terminal(20, 5, %W{ruby -I#{@pwd}/lib #{@pwd}/test/reline/yamatanooroti/multiline_repl --dialog fullwidth,scrollkey,scrollbar}, startup_message: 'Multiline REPL.')
+      unless Yamatanooroti.win? && Yamatanooroti.options.windows == :"legacy-conhost"
+        start_terminal(20, 5, %W{ruby -I#{@pwd}/lib #{@pwd}/test/reline/yamatanooroti/multiline_repl --dialog fullwidth,scrollkey,scrollbar}, startup_message: 'Multiline REPL.')
+      else
+        start_terminal(20, 5, %W{ruby -I#{@pwd}/lib #{@pwd}/test/reline/yamatanooroti/multiline_repl --dialog fullwidth,scrollkey,scrollbar}, startup_message: 'Multiline REPL.', codepage: 932)
+        omit "codepage 932 not supported" if !codepage_success?
+      end
       6.times{ write('j') }
       assert_screen(<<~'EOC')
         Multi
@@ -1237,7 +1242,12 @@ def test_dialog_with_fullwidth_chars
 
     def test_dialog_with_fullwidth_chars_split
       ENV['RELINE_TEST_PROMPT'] = '> '
-      start_terminal(20, 6, %W{ruby -I#{@pwd}/lib #{@pwd}/test/reline/yamatanooroti/multiline_repl --dialog fullwidth,scrollkey,scrollbar}, startup_message: 'Multiline REPL.')
+      unless Yamatanooroti.win? && Yamatanooroti.options.windows == :"legacy-conhost"
+        start_terminal(20, 6, %W{ruby -I#{@pwd}/lib #{@pwd}/test/reline/yamatanooroti/multiline_repl --dialog fullwidth,scrollkey,scrollbar}, startup_message: 'Multiline REPL.')
+      else
+        start_terminal(20, 6, %W{ruby -I#{@pwd}/lib #{@pwd}/test/reline/yamatanooroti/multiline_repl --dialog fullwidth,scrollkey,scrollbar}, startup_message: 'Multiline REPL.', codepage: 932)
+        omit "codepage 932 not supported" if !codepage_success?
+      end
       6.times{ write('j') }
       assert_screen(<<~'EOC')
         Multil