✅🚧 Omit 1 DataLite test for TruffleRuby

This is a real edge-case... one which I included only for completeness.
We _should not_ be making any recursive `Data` objects in `Net::IMAP`.

Author: nevans

test/net/imap/test_data_lite.rb

@@ -154,6 +154,8 @@ def test_inspect
       end
 
       def test_recursive_inspect
+        omit_if_truffleruby "TruffleRuby fails with a stack overflow: " \
+                            "https://github.com/oracle/truffleruby/issues/3847"
         klass = Data.define(:value, :head, :tail) do
           def initialize(value:, head: nil, tail: nil)
             case tail