git: openjdk/loom: fibers: More tests with known issues are excluded.

[duke]

Changeset: e6c41b36
Author:    lmesnik <leonid.mesnik at oracle.com>
Date:      2020-10-16 11:37:37 +0000
URL:       https://git.openjdk.java.net/loom/commit/e6c41b36

More tests with known issues are excluded.

! test/hotspot/jtreg/ProblemList-vthread.txt