ggml webgpu: add support for soft_max, optimize rms_norm (#16357)
* Add inplace softmax
* Move rms_norm to split row approach
* Update debug for supports_op
* clean up debug statements
* Update tests/test-backend-ops.cpp
Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>
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Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>