[9.0] Upgrade zlib-ng to 2.2.1

[carlossanlop]

Backport of #105771 to release/9.0

/cc @carlossanlop @jkotas

Customer Impact

• Customer reported
• Found internally

Changes in this PR:

• Update the native vendored version of zlib-ng to the latest release 2.2.1, released on July 2nd.
• Applies a patch that has already been sent upstream to fix some cmake errors due to missing explicit castings and asserts.
• Removes the custom allocator we were using. It's no longer needed.
• Also updates some tests that were comparing the file sizes for compression ratios that are too close to each other, which are cases where it cannot be guaranteed that the expected file size differences will always be seen.
• Updated the licensing files.

Regression

• Yes
• No

Testing

CI results succeeded.

Risk

Low.

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