[Wisp] Keep aligning Socket.isConnected() with the normal OpenJDK returning result

[zhengxiaolinX]

Summary: Socket.connect() in Wisp's implementation, uses nio SocketChannel's logic to prevent blocking when Socket is used. However, OpenJDK's isConnected() returns true after successfully connecting even if the socket gets closed. This will break consistency so we shall fix this.

Test Plan: newly-added ServerSocketConnectionTest.java

Reviewed-by: D-D-H

Issue: #437

[zhengxiaolinX]

@D-D-H May want to take a look? Thank you.

[zhengxiaolinX]

Tests passed.

good

My pleasure to get a review from you. @D-D-H

This patch only affects Wisp and the impact is low. One reviewer is enough.

/reviewers 1

Gotta go.