RFR: JDK-8268147: need to update reference to testng module for jtreg6

[Naoto Sato]

On Wed, 2 Jun 2021 22:22:22 GMT, Jonathan Gibbons <jjg at openjdk.org> wrote:

> Please review a test fix to refer to the new name of the TestNG module.

Marked as reviewed by naoto (Reviewer).

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PR: https://git.openjdk.java.net/jdk/pull/4325