RFR: 8246805: Incorrect copyright header in TestInvalidTieredStopAtLevel.java

[jiefu(傅杰)]

Hi all,

May I get reviews for this tiny fix, which just updates the license to be GPLv2 only (not GPLv2+CPE)?

JBS:    https://bugs.openjdk.java.net/browse/JDK-8246805
Webrev: http://cr.openjdk.java.net/~jiefu/8246805/webrev.00/

Thanks a lot.
Best regards,
Jie