Add `isOther` and `available` methods to `FileChannelImpl` and the interfaces to native code and use these in `ChannelInputStream` to work around cases where a wrapped `FileChannelImpl` is not really seekable.
------------- Commit messages: - 8233451: (fs) Files.newInputStream() cannot be used with character special files Changes: https://git.openjdk.org/jdk/pull/21508/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21508&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8233451 Stats: 204 lines in 11 files changed: 188 ins; 0 del; 16 mod Patch: https://git.openjdk.org/jdk/pull/21508.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/21508/head:pull/21508 PR: https://git.openjdk.org/jdk/pull/21508
