[PROPOSAL] backport GEODE-8651 to 1.13, 9.10, 9.9

[Xiaojian Zhou]

Hi, all:

The fix is to resolve a hang when Connection called notifyHandshakeWaiter the 
2nd time and cleared the NioFilter’s unwrapped buffer by mistake.

The 2nd call should consider if the 1st call has finished handshake. If yes, do 
nothing. The fix is fully tested and has no risk. This problem exists in 
earlier versions and should be backported.

Regards

Xiaojian Zhou