RFR of JDK-8019538: TEST_BUG: java/rmi/activation/rmidViaInheritedChannel tests may fail

[Hamlin Li]

Would you please review the fix for below bug?

bug: https://bugs.openjdk.java.net/browse/JDK-8019538
webrev: http://cr.openjdk.java.net/~mli/8019538/webrev.00/

There are 4 issues in the bug,
2 in RmidViaInheritedChannel.java:  "port in use" in registry, "port in 
use" in rmid start.
2 InheritedChannelNotServerSocket.java: "port in use" in registry, "port 
in use" in rmid start.

This patch fixes 2 issues in RmidViaInheritedChannel, and only "port in 
use" in registry in InheritedChannelNotServerSocket.
The "port in use" in rmid in InheritedChannelNotServerSocket is little 
bit hard, as it intends to test rmid when inherited channel not work. 
Currently the only solution in my mind is to retry when rmid fails with 
"port in use", but as we discussed earlier, it's not a good solution as 
it might impact other programs or tests, and it's not efficient.
So I hope to push the fix for the other issues first to improve the 
stability of RMI tests, and keep studying if there are other better 
solutions for the "port in use" in rmid in InheritedChannelNotServerSocket.

Thank you
-Hamlin