RFR [9] 8041924: [TESTBUG] sun/net/www/http/ChunkedOutputStream/checkError.java fails on some systems

[Chris Hegarty]

This test has been seen to fail intermittently. There is an assumption in the 
test that the client-side will fill the outgoing TCP buffer by writing 1 megabyte
of data, allowing for the server-side to close the connection out from under
it. This is the crux of the test. By slowing down the writes on the client-side
we can eliminate this assumption. The remainder of the changes just
modernise the code, and remove many unnecessary synchronization points.

http://cr.openjdk.java.net/~chegar/8041924/
https://bugs.openjdk.java.net/browse/JDK-8041924

-Chris.