Fix an assertion that was too strong

git-svn-id: https://llvm.org/svn/llvm-project/lnt/trunk@218902 91177308-0d34-0410-b5e6-96231b3b80d8

lnt/tests/nt.py

@@ -1238,7 +1238,7 @@ def check(self):
         assert self.compile_status is not None, msg
         assert self.execution_status is not None, msg
         assert self.compile_time is not None, msg
-        assert self.execution_time is not None, msg
+
         self.valid = True
 
     def is_rerunable(self):