RFR: 8206006: Build failed on Windows

[Robin Westberg]

Hi all,

Please review this small fix for a build break (windows without precompiled headers only) introduced by 8003209. 

Issue: https://bugs.openjdk.java.net/browse/JDK-8206006 <https://bugs.openjdk.java.net/browse/JDK-8206006>
Webrev: http://cr.openjdk.java.net/~rwestberg/8206006/webrev.00/ <http://cr.openjdk.java.net/~rwestberg/8206006/webrev.00/>
Testing: building windows-x64-slowdebug with --disable-precompiled-headers, local build and run on Mac of the affected unit test.

Best regards,
Robin