Feature map uses a significant amount of memory after loading a shared cache

[bdash]

Version and Platform (required):

• Binary Ninja Version: 5.2.8071-dev Ultimate, bab15a22
• OS: macos
• OS Version: 15.5
• CPU Architecture: arm64

Bug Description:
After opening a macOS shared cache and loading a couple of images, the feature map ends up with around 100MB of data allocated that represents the rendered version of the mapped memory regions. That feels excessive given that it is by default displayed in a view roughly 64 x [display height] pixels tall. On my Mac that's roughly 64 x ~1350, which should be representable in less than 100KB of memory.

Steps To Reproduce:

1. Open /System/Cryptexes/OS/System/Library/dyld/dyld_shared_cache_arm64e
2. Load a CoreFoundation, Foundation, AppKit, and CFNetwork.
3. Check the memory usage of the feature map

Expected Behavior:
Less.