RFR: 8303684: Lift upcall sharing mechanism to AbstractLinker (mainline)

[Maurizio Cimadamore]

On Mon, 6 Mar 2023 18:40:47 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

> Port of: https://github.com/openjdk/panama-foreign/pull/791 which lifts the sharing mechanism for upcall stubs to AbstractLinker. 
> 
> This also speeds up upcall stub linking:

Looks good (already reviewed on Panama repo)

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Marked as reviewed by mcimadamore (Reviewer).

PR: https://git.openjdk.org/jdk/pull/12883