Skip charmap test

Author: msimacek

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

@@ -21,6 +21,7 @@
 *graalpython.lib-python.3.test.test_unicode.UnicodeTest.test_casefold
 *graalpython.lib-python.3.test.test_unicode.UnicodeTest.test_center
 *graalpython.lib-python.3.test.test_unicode.UnicodeTest.test_codecs
+*graalpython.lib-python.3.test.test_unicode.UnicodeTest.test_codecs_charmap
 *graalpython.lib-python.3.test.test_unicode.UnicodeTest.test_codecs_idna
 *graalpython.lib-python.3.test.test_unicode.UnicodeTest.test_codecs_utf7
 *graalpython.lib-python.3.test.test_unicode.UnicodeTest.test_codecs_utf8

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

@@ -2148,6 +2148,8 @@ def test_codecs(self):
         for encoding in ('utf-8',):
             self.assertEqual(str(u.encode(encoding),encoding), u)
 
+    # Java charsets sometimes produce a bit different results
+    @support.impl_detail(graalvm=False)
     def test_codecs_charmap(self):
         # 0-127
         s = bytes(range(128))