RFR: 8275640 (win) java.net.NetworkInterface issues with IPv6-only environments

[Daniel Jeliński]

Clean up of various issues related to error handling and memory management

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Commit messages:
 - Fix memory leak
 - Fixup getAllInterfacesAndAddresses
 - Fixup getAddrsFromAdapter
 - Fixup enumAddresses_win
 - Fixup enumAddresses_win_ipaddrtable
 - Remove special handling for GetIfTable failure

Changes: https://git.openjdk.java.net/jdk/pull/6090/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6090&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8275640
  Stats: 26 lines in 2 files changed: 11 ins; 10 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6090.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6090/head:pull/6090

PR: https://git.openjdk.java.net/jdk/pull/6090