8165687: Fix license and copyright headers in jd9 under hotspot/test
Summary: Legal notices and Oracle copyrights were updated (white and blank space, commas) in tests files for uniformity to meet Oracle requirements.
Reviewed-by: dholmes, iris
Contributed-by: Stanislav Smirnov <stanislav.smirnov@oracle.com>, Vassili Igouchkine <vassili.igouchkine@oracle.com>

8159073: : Error handling incomplete when creating GC threads lazily
Reviewed-by: drwhite, tschatzl, sangheki

8157620: Guarantee in run_task(task, num_workers) fails
Reviewed-by: tschatzl, drwhite

8153222: [TESTBUG] Move tests in stress/gc to gc/stress
Reviewed-by: dfazunen, jwilhelm