Implement C API function PyUnicode_DecodeLatin1

Author: fangerer

graalpython/com.oracle.graal.python.cext/src/unicodeobject.c

@@ -689,3 +689,14 @@ UPCALL_ID(PyUnicode_Split)
 PyObject* PyUnicode_Split(PyObject *s, PyObject *sep, Py_ssize_t maxsplit) {
     return UPCALL_CEXT_O(_jls_PyUnicode_Split, native_to_java(s), native_to_java(sep), maxsplit);
 }
+
+// taken from CPython "Objects/unicodeobject.c"
+PyObject *
+PyUnicode_DecodeLatin1(const char *s,
+                       Py_ssize_t size,
+                       const char *errors)
+{
+    /* Latin-1 is equivalent to the first 256 ordinals in Unicode. */
+    return _PyUnicode_FromUCS1((const unsigned char*)s, size);
+}
+

graalpython/lib-graalpython/modules/hpy/test/test_hpyunicode.py

@@ -163,7 +163,6 @@ def test_AsUTF8AndSize(self):
         assert mod.g(b'A'.decode('utf-8')) == ord('A')
         assert mod.g(b'A\0'.decode('utf-8')) == ord('A')
 
-    @pytest.mark.skip(reason="GR-40178")
     def test_DecodeLatin1(self):
         mod = self.make_module("""
             HPyDef_METH(f, "f", f_impl, HPyFunc_O)