RFR: 7105952 Improve finalisation for FileInputStream/FileOutputStream/RandomAccessFile

[Seán Coffey]

Alan,

as discussed, this is the proposed backport of 7105952 to jdk7u6. It's 
baked in Jdk 8 for some time now without issue. The patch is slightly 
different given that the JDK 7 repo had CR 7101658 to backout the round 
1 fix.

Resulting code should be identical though. I thought I'd create a webrev 
& RFR before seeking approval in 7u.

http://cr.openjdk.java.net/~coffeys/webrev.7105952.jdk7/

regards,
Sean.