Use located cache for Objective-C header info lookup

[p-x9]

Summary

• read Objective-C header info entries from the cache containing the header optimization table
• avoid a second cache hierarchy traversal after locating that table
• reuse DyldCacheLoaded.machO(at:) for 32-bit protocol relative-list resolution

Rationale

objc4 defines header_info entries as the trailing array of objc_headeropt_ro_t, while dyld resolves the table start from headerInfoROCacheOffset. Once the cache containing the RO table is known, its entries should be read from that same cache instead of searching the hierarchy again.

The loaded-image protocol path also duplicated the same RO-to-Mach-O lookup and hard-coded the 64-bit RO table. Reusing the existing helper keeps the 32-bit and 64-bit paths consistent.

Validation

• swift test
• swift test --filter MachOObjCSectionTests/testImageInfoInImage
• git diff --check

[Copilot]

Pull request overview

This PR refactors Objective-C header-info lookup to reuse the dyld-cache helper that already resolves Mach-O images by image index, and updates cache-backed header optimization table lookups to read header-info entries from the same located cache (avoiding redundant hierarchy traversal).

Changes:

• Simplifies ObjCProtocolRelativeListList32 loaded-image resolution by reusing DyldCacheLoaded.machO(at:).
• Updates DyldCache._machO(at:) to read headerInfos from the cache that actually contained the located header optimization RO table (both 64-bit and 32-bit paths).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
Sources/MachOObjCSection/Model/Protocol/ObjCProtocolRelativeListList.swift	Switches 32-bit protocol relative-list resolution to use the shared dyld-cache Mach-O lookup helper.
Sources/MachOObjCSection/Extension/DyldCache+.swift	Ensures header-info arrays are read from the located cache containing the RO table, reducing redundant hierarchy traversal.

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