RFR: 8336755: Remove unused UNALIGNED field from Direct non-byte Buffers

[Andrey Turbanov]

Actually it's used only by `DirectByteBuffer` and `DirectByteBufferR` classes.

List of affected classes:
`DirectCharBufferS`, `DirectCharBufferU`,
`DirectDoubleBufferS`, `DirectDoubleBufferU`,
`DirectFloatBufferS`, `DirectFloatBufferU`,
`DirectIntBufferS`, `DirectIntBufferU`,
`DirectLongBufferS`, `DirectLongBufferU`,
`DirectShortBufferS`, `DirectShortBufferU`

Tested `test/jdk/java/nio` on Linux x64 release.

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Commit messages:
 - remove 'protected' modifier
 - [PATCH] Remove unused 'static boolean UNALIGNED' field from non-byte Buffers implementations

Changes: https://git.openjdk.org/jdk/pull/20233/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20233&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8336755
  Stats: 10 lines in 1 file changed: 2 ins; 8 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/20233.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20233/head:pull/20233

PR: https://git.openjdk.org/jdk/pull/20233