RFR: 8300235: Use VarHandle access in Image(Input | Output)StreamImpl classes

[Per Minborg]

On Wed, 25 Jan 2023 16:39:04 GMT, Per Minborg <pminborg at openjdk.org> wrote:

> This PR suggests improving performance by using the newly introduced class `jdk.internal.util.ByteArray` to improve packing/unpacking operations.
> 
> The PR also proposes adding a `ByteArrayLittleEndian` class for support for little endian packing/unpacking.

Given the way the benchmarks are written, I suspect the actual performance gains are higher than indicated by the figures above. The benchmark likely spends more time in preparing for the call (e.g. checking, looping) than in the actual target method.

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PR: https://git.openjdk.org/jdk/pull/12204