Remove mappingproxy.update

Author: msimacek

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

@@ -27,6 +27,7 @@
 *graalpython.lib-python.3.test.test_types.MappingProxyTests.test_get
 *graalpython.lib-python.3.test.test_types.MappingProxyTests.test_iterators
 *graalpython.lib-python.3.test.test_types.MappingProxyTests.test_len
+*graalpython.lib-python.3.test.test_types.MappingProxyTests.test_methods
 *graalpython.lib-python.3.test.test_types.SimpleNamespaceTests.test_as_dict
 *graalpython.lib-python.3.test.test_types.SimpleNamespaceTests.test_attrdel
 *graalpython.lib-python.3.test.test_types.SimpleNamespaceTests.test_attrget

graalpython/lib-graalpython/_mappingproxy.py

@@ -48,7 +48,4 @@ def __repr__(self):
     return "".join(["mappingproxy({", dstr, "})"])
 mappingproxy.__repr__ = __repr__
 mappingproxy.__str__ = __repr__
-
-
-mappingproxy.update = dict.update
 mappingproxy.__hash__ = dict.__hash__