[foreign-memaccess+abi] RFR: Break out functionality to internal class

[Maurizio Cimadamore]

On Thu, 22 Sep 2022 08:43:20 GMT, Per Minborg <duke at openjdk.org> wrote:

> This PR brakes out functionality from `MemorySegment` into an internal class.

Looks good

Marked as reviewed by mcimadamore (Committer).

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PR: https://git.openjdk.org/panama-foreign/pull/732