ggml-webgpu: parameterize submission size and add iOS specific limits (#21533)
* Work towards removing bitcast
* Move rest of existing types over
* Add timeout back to wait and remove synchronous set_tensor/memset_tensor
* move to unpackf16 for wider compatibility
* cleanup
* Remove deadlock condition in free_bufs
* Start work on removing parameter buffer pools
* Simplify and optimize further
* simplify profile futures
* Fix stride
* Try using a single command buffer per batch
* formatting
* Add parameters for different browsers in-flight submissions
* Update handling of batch size too
* Throttle ios as much as possible
* Increase timeout for llvm-pipe testing