RFR(trivial): 8234183: [TESTBUG] tools/javac/api/TestModuleUnnamedPackage.java fails to compile

[Jie Fu]

Hi all,

May I get reviews for this small fix?

JBS:    https://bugs.openjdk.java.net/browse/JDK-8234183
Webrev: http://cr.openjdk.java.net/~jiefu/8234183/webrev.00/

And I need a sponsor.

Thanks a lot.
Best regards,
Jie