Skip finalization test

Author: msimacek

graalpython/com.oracle.graal.python.test/src/tests/unittest_tags/test_class.txt

@@ -1,6 +1,7 @@
 *graalpython.lib-python.3.test.test_class.ClassTests.testBadTypeReturned
 *graalpython.lib-python.3.test.test_class.ClassTests.testBinaryOps
 *graalpython.lib-python.3.test.test_class.ClassTests.testConstructorErrorMessages
+*graalpython.lib-python.3.test.test_class.ClassTests.testDel
 *graalpython.lib-python.3.test.test_class.ClassTests.testForExceptionsRaisedInInstanceGetattr2
 *graalpython.lib-python.3.test.test_class.ClassTests.testGetSetAndDel
 *graalpython.lib-python.3.test.test_class.ClassTests.testHashStuff

graalpython/lib-python/3/test/test_class.py

@@ -445,6 +445,7 @@ def __delattr__(self, *args):
         del testme.cardinal
         self.assertCallStack([('__delattr__', (testme, "cardinal"))])
 
+    @support.impl_detail("finalization", graalvm=False)
     def testDel(self):
         x = []