Fix screen corruption on Xbox when in rendergraph mode

[FrancescoC-unity]

This was an hard one to track :-)

Very long story very short, the issue was due to the fact that a memory stomp happened on the TAA history by another unidentified target.
The reason why this happened with Motion Blur on is that the creation of a transient texture with the same color format of the scene color/history, the texture pool would end up in a state in which reuse was incorrectly triggered even though it was not the transient texture doing the stomping itself.

Adding the fastmem condition to the hash used to determine reuse seems to fix the issue.

[TomasKiniulis]

Built Xbox player on template, went through RenderGraph Clear Render Targets, Disable Pass Culling, Immediate mode debug modes. No rendering issues occur anymore.