RFR: 8275319 java.net.NetworkInterface throws java.lang.Error instead of SocketException

[Daniel Jeliński]

Per Java documentation, "[Error](https://github.com/openjdk/jdk/blob/master/src/java.base/share/classes/java/lang/Error.java#L30) [..] indicates serious problems that a reasonable application should not try to catch". Failure to enumerate network interfaces or addresses is not a serious enough situation; many applications can recover from this pretty easily.

All native methods (except `init()`) in [NetworkInterface](https://github.com/openjdk/jdk/blob/master/src/java.base/share/classes/java/net/NetworkInterface.java#L436) are declared with `throws SocketException`, so throwing SocketExceptions instead of Errors will match the declared interface.

Unix version of [NetworkInterface](https://github.com/openjdk/jdk/blob/master/src/java.base/unix/native/libnet/NetworkInterface.c#L1189) already throws `SocketException`s in similar situations, and does not throw `Error` under any circumstances.

I searched the bug database and mail archives, but could not find any discussion on the topic; if there's a reason to keep throwing `Error`s, I couldn't find it.

`tier1` tests pass, `java.net` tests pass. No new regression tests as I couldn't find any list of steps to reproduce the problem.

I don't have write access to JBS. I could use some help with creating a ticket.

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Commit messages:
 - Throw SocketExceptions instead of Errors in NetworkInterface

Changes: https://git.openjdk.java.net/jdk/pull/5956/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5956&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8275319
  Stats: 11 lines in 2 files changed: 0 ins; 0 del; 11 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5956.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5956/head:pull/5956

PR: https://git.openjdk.java.net/jdk/pull/5956