Add testcase related to commit 0d26a79f2c.

cover up the case when there's at least a token before 'namespace %type% { }'.

test/testsimplifytokens.cpp

@@ -2409,6 +2409,12 @@ private:
             ASSERT_EQUALS("", tok(code));
         }
 
+        {
+            const char code[] = "; namespace std { }";
+
+            ASSERT_EQUALS(";", tok(code));
+        }
+
         {
             const char code[] = "using namespace std; namespace a{ namespace b{ void f(){} } }";