fix assertion number.

On parallel test, there are additional tests because of implicit
checkers which are enabled on 84cbce3d88.

tool/test/testunit/test_parallel.rb

@@ -112,7 +112,7 @@ module TestParallel
         result = Marshal.load($1.chomp.unpack("m")[0])
 
         assert_equal(5, result[0])
-        assert_equal(2, result[1])
+        assert_equal(17, result[1])
         assert_kind_of(Array,result[2])
         assert_kind_of(Array,result[3])
         assert_kind_of(Array,result[4])