git: openjdk/loom: fibers: Update property for custom configs usage.

[duke]

Changeset: 5bff632f
Author:    lmesnik <leonid.mesnik at oracle.com>
Date:      2020-11-12 12:38:32 +0000
URL:       https://github.com/openjdk/loom/commit/5bff632f

Update property for custom configs usage.

! test/failure_handler/src/share/classes/jdk/test/failurehandler/Utils.java