GS/HW: Texture cache refactoring

[stenzek]

Description of Changes

• Perform target lookup before source (in most cases).
• Support differing page pitch for P8 conversion.
• Centralize tex-is-fb detection and correction.
• Reduce copy size in many cases.
• Transfer clear when resizing a texture.
• Scale factor is now applied per-draw rather than global config.
• Count stretches in texture cache as copies.
• Sample and test depth buffer concurrently where safe.

Rationale behind Changes

Fixing a bunch of Vulkan spec violations, cleaning up shuffle handling a bit, making the TC slightly easier to work with.

Fixes fog effect in Crash: WoC without CPU readback. Currently only works at native.

Suggested Testing Steps

No current regressions in the runner, but there's probably still some broken games.