Remove unstable test

- This test will *always* break if executed after the 19th of a month

Author: lauft

test/datetime.t.cpp

@@ -924,7 +924,6 @@ int main (int, char**)
 
     Datetime r37 ("19th");
     t.is (r37.day (),      19,        "'19th' --> 19");
-    t.ok (r37 >= now,                 "'19th' > 'now'");
 
 /*
     // Phrases.