Guard static variable first

* ext/openssl/ossl_asn1.c (Init_ossl_asn1): register the static
  variable to grab an internal object, before creating the object.
  otherwise the just-created object could get collected during the
  global variable list allocation.  [Bug #16196]

ext/openssl/ossl_asn1.c

@@ -1823,8 +1823,8 @@ do{\
     rb_define_method(cASN1EndOfContent, "initialize", ossl_asn1eoc_initialize, 0);
     rb_define_method(cASN1EndOfContent, "to_der", ossl_asn1eoc_to_der, 0);
 
-    class_tag_map = rb_hash_new();
     rb_global_variable(&class_tag_map);
+    class_tag_map = rb_hash_new();
     rb_hash_aset(class_tag_map, cASN1EndOfContent, INT2NUM(V_ASN1_EOC));
     rb_hash_aset(class_tag_map, cASN1Boolean, INT2NUM(V_ASN1_BOOLEAN));
     rb_hash_aset(class_tag_map, cASN1Integer, INT2NUM(V_ASN1_INTEGER));

test/openssl/test_asn1.rb

@@ -635,6 +635,11 @@ class  OpenSSL::TestASN1 < OpenSSL::TestCase
     assert_equal data, seq.entries
   end
 
+  def test_gc_stress
+    skip "very time consuming test"
+    assert_ruby_status([{"RUBY_DEBUG"=>"gc_stress"}, "--disable-gems", "-ropenssl", "-eexit"], timeout: 20)
+  end
+
   private
 
   def B(ary)