TextureCache shouldn't derive from UnityEngine.Object

1. No need. 2. When it does, and it's created with new(), ==null checks
don't work as expected and the objects newer get cleaned up, leaking
memory.

Assets/ScriptableRenderLoop/common/TextureCache.cs

 }
 
 
-public abstract class TextureCache : Object
+public abstract class TextureCache
 {
     protected int m_NumMipLevels;