skip on RUBY_ISEQ_DUMP_DEBUG=to_binary

9b535f3ff7 does not support ISeq#to_binary.
To make CI green, skip this test temporarily.

Please fix this issue and revert this patch.

test/ruby/test_literal.rb

@@ -187,6 +187,7 @@ class TestRubyLiteral < Test::Unit::TestCase
   if defined?(RubyVM::InstructionSequence.compile_option) and
     RubyVM::InstructionSequence.compile_option.key?(:debug_frozen_string_literal)
     def test_debug_frozen_string
+      skip if ENV['RUBY_ISEQ_DUMP_DEBUG'] == 'to_binary'
       src = '_="foo-1"'; f = "test.rb"; n = 1
       opt = {frozen_string_literal: true, debug_frozen_string_literal: true}
       str = RubyVM::InstructionSequence.compile(src, f, f, n, **opt).eval