INT-2911 IO Exceptions Not Logged as ERROR

TcpNetConnection IO errors were only logged under DEBUG.

Code was added to suppress the error log when the exception
was due to a normal close. This inadvertently suppressed all
ERROR logs.

Capture a local copy of this.noReadErrorOnClose before closing
the socket after an exception.

Add test case to ensure ERROR log is emitted.
INT-2911 Polishing - PR Comments