[pr/110] RFR: 8317812: [Lilliput] Make C2 LoadNKlassCompactHeader more robust

[Aleksey Shipilev]

On Wed, 11 Oct 2023 08:26:20 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Ah, ok then. I missed that original assert also checked for `4`. Weird.
>
> On the other hand, this suggests that we can pass `$mem$$index$Register` right away?
> 
> https://github.com/openjdk/lilliput/pull/111/files#diff-018aa61d1a7aafcf70a535fcd40a318a4bd6511fd40ac39ce4be90cc52216749L7350

In fact, I don't quite see why `x86_64.ad` cannot do what `aarch64.ad` does:


__ load_nklass_compact($dst$$Register, $mem$$base$$Register, $mem$$index$$Register, $mem$$scale, $mem$$disp);

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PR Review Comment: https://git.openjdk.org/lilliput/pull/111#discussion_r1354397121