RFR: 8340524: Remove NarrowPtrStruct

[Aleksey Shipilev]

On Sat, 21 Sep 2024 04:19:13 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

> Please review this change which removes the class NarrowPtrStruct. The only
> place it was still being used was as the type of CompressedOops::_narrow_oops.
> Instead, we move the members from NarrowPtrStruct directly into
> CompressedOops, flattening its structure.
> 
> Testing: mach5 tier1-3
> Tiers 2&3 run serviceability tests that hit the changes to that component.

Agreed, good cleanup.

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Marked as reviewed by shade (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/21115#pullrequestreview-2319662213