Reuse cached full dyld cache for lookups

[p-x9]

Summary

• route DyldCache.locateValue through an already-associated FullDyldCache
• add FullDyldCache.locateValue helpers that search the main cache and its subcaches
• exclude the cache already checked by the caller so each cache is resolved at most once
• reuse cached full-cache address lookup APIs from MachOFile

Why

Lookup paths previously traversed or reopened individual dyld cache files even when a complete FullDyldCache was already available. This change reuses the associated full-cache view, keeps main/subcache lookup behavior consistent, and avoids evaluating the same subcache twice during delegated resolution.

Impact

Mach-O Objective-C metadata and address resolution can reuse existing full-cache state instead of reconstructing cache access paths, while preserving fallback behavior for standalone DyldCache instances.

Validation

• swift build
• swift test --filter MachOObjCSectionTests.testCategories2InCacheFile
• verified main-cache-first lookup and single-visit behavior with focused regression checks during development

[Copilot]

Pull request overview

This PR optimizes dyld cache lookups by reusing an already-associated FullDyldCache when available, avoiding redundant cache traversals/reopens while keeping main-cache-first behavior consistent across main/subcaches.

Changes:

• Routes MachOFile dyld-cache address resolution through cache._cachedFullCache when present.
• Adds FullDyldCache.locateValue helpers to resolve values across main cache + subcaches with optional exclusion.
• Updates DyldCache.locateValue to delegate to the cached FullDyldCache (excluding the already-checked cache) when available.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
Sources/MachOObjCSection/Extension/MachOFile+.swift	Reuses cached full-cache state for address→cache/fileOffset lookups and Objective-C selector base offset resolution.
Sources/MachOObjCSection/Extension/FullDyldCache+.swift	Introduces hierarchy-wide locateValue helpers with exclusion support.
Sources/MachOObjCSection/Extension/DyldCache+.swift	Delegates locateValue to an associated FullDyldCache to avoid re-checking caches.

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