Fix memory consumption estimate in test_unicode_repr_wide
(on Martin's buildbot it still seems a bit inaccurate)
diff --git a/Lib/test/test_bigmem.py b/Lib/test/test_bigmem.py
index 4d7535c..28e69a0 100644
--- a/Lib/test/test_bigmem.py
+++ b/Lib/test/test_bigmem.py
@@ -715,7 +715,7 @@
         finally:
             r = s = None
 
-    @bigmemtest(size=_2G // 5 + 1, memuse=ucs4_char_size + ascii_char_size * 10)
+    @bigmemtest(size=_2G // 5 + 1, memuse=ucs4_char_size * 2 + ascii_char_size * 10)
     def test_unicode_repr_wide(self, size):
         char = "\U0001DCBA"
         s = char * size