RFR 8216978: Drop support for pre JDK 1.4 SocketImpl implementations

[Michael McMahon]

Hi,

This is another change which is part of the general cleanup of SocketImpls.
The change removes support for pre JDK 1.4 socketimpls which do not 
implement
the timed connect method. These SocketImpls have not been compilable
since 1.4 and limited runtime support has been provided since then, 
which is now being removed.

Webrev
-------
http://cr.openjdk.java.net/~michaelm/8216978/webrev.1/

CSR
----
https://bugs.openjdk.java.net/browse/JDK-8222546


Thanks,
Michael.