Finalizer and NoGC

[wks]

The following error happens during https://github.com/mmtk/ruby/actions/runs/10820356413/job/30039916607, running NoGC.

  [328/915] 17345=test_json_tree
  /home/runner/work/ruby/ruby/src/tool/lib/test/unit/parallel.rb: warning: Exception in finalizer #<Tempfile::FinalizerManager:0x000002000230d740 @open_files={}, @path="/tmp/rubytest.2ihv13/TestRDocParserRuby20240912-17349-rn914l", @pid=17349, @unlinked=true>
  /home/runner/work/ruby/ruby/src/lib/tempfile.rb:387:in 'IO#close': SIGTERM (SignalException)
  	from /home/runner/work/ruby/ruby/src/lib/tempfile.rb:387:in 'Tempfile::FinalizerManager#call'

There may be some subtle interaction between TempFile (which uses ObjectSpace::define_finalizer) that is not handled properly in NoGC.