test-backend-ops : add performance eval mode + improve CUDA repeat and binary broadca...

test-backend-ops : add performance eval mode + improve CUDA repeat and binary broadcast ops performance (#636)

* ggml-cuda : implement repeat with bin_bcast

* ggml-cuda : change supports_op for mul_mat to match compute_forward

* test-backend-ops : add performance eval mode

* improve formatting

* add sd test cases

* fix test case

* ggml-cuda : bin_bcast: better block sizes, two elements per thread

* metal : add dim3 broadcast support for mul mat

* cleanup

* typo

* metal : enable mul mat-vec for dim2 > 1

* metal : mul mat-vec support dim3 broadcasts

ggml-ci

* ggml-cuda : fix bin_bcast for ne0=1
ggml-ci

* ggml-cuda : limit block size z dim to 64

* test-backend-ops : add test cases

* test-backend-ops : add warmup run, print test type before trying to compute

* ggml-cuda : bin_bcast: collapse dimensions when possible, add fallback kernel for large tensors
ggml-ci

* test-backend-ops : avoid division by zero

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Co-authored-by: Georgi Gerganov <redacted>