Issue python#28023: Fix python-gdb.py on old GDB versions

Replace int(value.address)+offset with value.cast(unsigned char*)+offset.

It seems like int(value.address) fails on old versions of GDB.

Tools/gdb/libpython.py

@@ -709,6 +709,7 @@ def write_repr(self, out, visited):
         out.write('}')
 
     def _get_entries(self, keys):
+        dk_nentries = int(keys['dk_nentries'])
         dk_size = int(keys['dk_size'])
         try:
             # <= Python 3.5
@@ -726,9 +727,12 @@ def _get_entries(self, keys):
         else:
             offset = 8 * dk_size
 
+        ent_addr = keys['dk_indices']['as_1'].address
+        ent_addr = ent_addr.cast(_type_unsigned_char_ptr()) + offset
         ent_ptr_t = gdb.lookup_type('PyDictKeyEntry').pointer()
-        ent_addr = int(keys['dk_indices']['as_1'].address) + offset
-        return gdb.Value(ent_addr).cast(ent_ptr_t), int(keys['dk_nentries'])
+        ent_addr = ent_addr.cast(ent_ptr_t)
+
+        return ent_addr, dk_nentries
 
 
 class PyListObjectPtr(PyObjectPtr):