8182554: Code for os::random() assumes long is 32 bits
Summary: And make updating the _rand_seed thread safe.
Reviewed-by: stuefe, kbarrett, stefank

8157455: Convert TestOS_test to GTest
Reviewed-by: dholmes, rehn

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>

8159364: Gtest unit tests does not support PCH
Reviewed-by: erikj, jwilhelm, gtriantafill

8148244: Finalize and integrate GTest implementation
Reviewed-by: jwilhelm, erikj
Contributed-by: stefan.karlsson@oracle.com, stefan.sarne@oracle.com, jesper.wilhelmsson@oracle.com, erik.helin@oracle.com, alexandre.iline@oracle.com, igor.ignatyev@oracle.com, erik.joelsson@oracle.com