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>

8042660: vm/mlvm/anonloader/stress/byteMutation failed with: assert(index >=0 && index < _length) failed: symbol index overflow
Summary: Detect zero length signatures and throw ClassFormatError before bad dereference occurs
Reviewed-by: coleenp, lfoltan, acorn, gtriantafill