RFR 8231427 (test) Warning cleanup in tests of java.io.Serializable

[Roger Riggs]

Please review cleanup of tests in java/io/Serializable. There are 
warnings for mis-use of
serialization methods and fields; some are intentional as they are the 
focus of the tests.
The test code had quite a few warnings about raw types, deprecated 
methods, and
missing serialVersionUIDs, and deprecated methods, etc.
Issue:
https://bugs.openjdk.java.net/browse/JDK-8231427

Webrev:
http://cr.openjdk.java.net/~rriggs/webrev-ser-test-cleanup-8231427-2/

Thanks, Roger