RFR: 8241800: Disable IPV6_MULTICAST_ALL to prevent interference from all multicast groups [v6]

[Michael McMahon]

> Hi,
> 
> Can I get the following change reviewed please? It disables the IPV6_MULTICAST_ALL socket option on UDP sockets on Linux systems which support the option (kernel version 4.20+). This has the effect of disabling the surprising default behavior of multicast sockets on Linux where sockets can receive packets sent to groups the receiver has not joined, if some other socket has joined that group on the same system.
> 
> The equivalent behavior has already been implemented for IPv4 sockets.
> 
> Thanks,
> Michael.

Michael McMahon has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 13 additional commits since the last revision:

 - Merge branch 'master' into ipv6opt
 - Test updates
 - test update
 - removed new test and added to existing Promiscuous test
 - test update
 - typo
 - review update
 - added test comment
 - Merge branch 'master' into ipv6opt
 - test fix
 - ... and 3 more: https://git.openjdk.org/jdk/compare/03514d1e...bd7ff0b6

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/14491/files
  - new: https://git.openjdk.org/jdk/pull/14491/files/14ea193c..bd7ff0b6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14491&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14491&range=04-05

  Stats: 6468 lines in 269 files changed: 4258 ins; 1191 del; 1019 mod
  Patch: https://git.openjdk.org/jdk/pull/14491.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14491/head:pull/14491

PR: https://git.openjdk.org/jdk/pull/14491