Fix the UtPrintx() routine such that the loop stops correctly.
Also improves the output to print the address, not just the data.

Note if UtPrintf is used, one sees the file/line of the UtPrintx
function, not the actual test location, so it is better to call
UT_BSP_DoText directly so it omits this extraneous info.

Adds an OS_SocketShutdown() wrapper around the BSD socket shutdown() API.
This allows a data transfer of a stream socket to be gracefully shut
down prior to socket closure.

Fix #964, UtPrintx function

Fix #960, add socket shutdown implementation