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>

8157957: ClassNotFoundException: jdk.test.lib.JDKToolFinder
Reviewed-by: coleenp, gtriantafill, mseledtsov, iignatyev, dholmes, dsamersoff

8136930: Simplify use of module-system options by custom launchers
Reviewed-by: coleenp, lfoltan, mchung

8154258: [TESTBUG] Various serviceability tests fail compilation
Summary: Replace sun.misc.Unsafe with jdk.internal.misc.Unsafe
Reviewed-by: chegar, kvn

8153737: Unsupported Module
Reviewed-by: alanb, mchung, psandoz

8140189: [TESTBUG] Get rid of "@library /../../test/lib" in jtreg tests
Summary: Use new external.lib.roots property in TEST.ROOT so /../../test/lib is not needed.
Reviewed-by: mseledtsov, sla, iklam

8081317: [NEWTEST] documented GC ratio tuning and new size options should be covered by regression tests
Reviewed-by: iignatyev, dfazunen