git: openjdk/loom: fibers: add needed sync to serviceability/thread/GetFrameCount/framecnt01 test

[duke]

Changeset: 9a5f9fc6
Author:    Serguei Spitsyn <serguei.spitsyn at oracle.com>
Date:      2021-10-26 02:18:44 +0000
URL:       https://git.openjdk.java.net/loom/commit/9a5f9fc603c5bcfbf2b7af2c86164b733449b242

add needed sync to serviceability/thread/GetFrameCount/framecnt01 test

! test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameCount/framecnt01/framecnt01.java