RFR 8168979: @implNote for invalid FilePermission

[Xuelei Fan]

On 12/13/2016 5:45 PM, Wang Weijun wrote:
> A major behavior change is that <<ALL FILES>> now implies an invalid permission, I hope this is good to minimize incompatibility.
Looks like two sides of the same coin.  If there is an invalid <<ALL 
FILES>> (not existing in practice, I think), it now implies all;  if no 
change on this point, <<ALL FILES>> does not imply invalid one.  The 
existing behavior looks more safe to me.  What's you concern to make 
this behavior change?

Otherwise, looks fine to me.

Xuelei