[perl #55620] [PATCH] Fix crash in src/ops/object.ops

[NotFound via RT]

Another attempt: this is a minimalistic change that does not broke any
test in parrot nor in rakudo, and can avoid segfaulting in other related
usages.

Index: src/pmc/namespace.pmc
===================================================================
--- src/pmc/namespace.pmc	(revisión: 28239)
+++ src/pmc/namespace.pmc	(copia de trabajo)
@@ -74,6 +74,7 @@
         PMC_data(SELF)                 =
                 mem_allocate_zeroed_typed(Parrot_NameSpace);
         PARROT_NAMESPACE(SELF)->vtable = PMCNULL;
+        PARROT_NAMESPACE(SELF)->_class = PMCNULL;
     }
 
 /*