GPU: Metal: Rebind storage buffers when their locations change.

[krajzeg]

When you change the pipeline to one that uses a different number of vertex/fragment uniform buffers, that moves the actual locations storage buffers should be bound to on the Metal side.

This PR makes the GPU Metal driver take that into account when changing the pipeline. Beforehand, buffers would not be rebound at their new locations, causing issues.

Description

The new code compares the previous and new pipeline when they change, and checks whether the base index of where storage buffers are located on the Metal side has changed (this is caused by uniform buffers pushing them higher/lower). If the base index has changed, it forces a rebind.

This logic is repeated for vertex and fragment storage buffers.

It's possible there are similar bugs to this one if other resource types also share indices on the Metal side in this way, eg. storage textures. It would probably be good if someone more familiar with the Metal backend checked whether that is the case, possibly adding more forced rebinds on pipeline change if needed.

Existing Issue(s)

Fixes #14652.

[slouken]

@TheSpydog, do we need similar changes for other resource types?