[foreign-memaccess+abi] Integrated: Improve strlen performance

[Per Minborg]

On Mon, 14 Aug 2023 09:52:10 GMT, Per Minborg <pminborg at openjdk.org> wrote:

> This PR suggests removing the use of native calls for strlen and instead use Java implementations.
> 
> The PR also suggest performance improvements for quad word strlen.
> 
> Here are some benchmarks that compares the performance of the new proposed methods with the performance of the JDK 21 variants (called "legacy" methods):
> 
> <img width="2596" alt="image" src="https://github.com/openjdk/panama-foreign/assets/7457876/c785f341-c826-4e3e-bf56-8387b1e96010">

This pull request has now been integrated.

Changeset: 51582b52
Author:    Per Minborg <pminborg at openjdk.org>
URL:       https://git.openjdk.org/panama-foreign/commit/51582b52592d6cc71100726a0a0b6b174f30c609
Stats:     562 lines in 5 files changed: 399 ins; 51 del; 112 mod

Improve strlen performance

Reviewed-by: mcimadamore

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PR: https://git.openjdk.org/panama-foreign/pull/862