8213305: Fix legal headers in test/java/math

Reviewed-by: stuefe
Backport-of: e21d8fe

test/jdk/java/math/BigInteger/PrimeTest.java

@@ -4,9 +4,7 @@
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.  Oracle designates this
- * particular file as subject to the "Classpath" exception as provided
- * by Oracle in the LICENSE file that accompanied this code.
+ * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or