ggml : extend ggml_pool_1d + metal (#16429)
* chore: resolve conflicts
* feat: ggml metal impl
* fix: ggml_metal_kargs_pool_1d struct
* fix: require contiguous input
* chore: test pool_1d
* chore: limit pool1d test cases to p0=0 and s0=k0 to conform with asserts
* chore: add p0 and s0 to testing
* fix: allow padding for cpu and metal
* Update ggml/src/ggml-metal/ggml-metal.metal
* fix: correct single-threaded loop
* ggml : cleanup
* tests : add ne[1] != 1 tests
* fix: ne[1] handling in np
* cont : fixes
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Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>
