test-backend-ops: add support for specifying output format (llama/14368)

test-backend-ops: add support for specifying output format (llama/14368)

* test-backend-ops: add support for specifying output format

Signed-off-by: Xiaodong Ye <redacted>
* Address review comments

Signed-off-by: Xiaodong Ye <redacted>
* Add build_commit and build_number in test_result

Signed-off-by: Xiaodong Ye <redacted>
* Address review comments

Signed-off-by: Xiaodong Ye <redacted>
* refactor

Signed-off-by: Xiaodong Ye <redacted>
* Get build commit from ggml_commit()

Signed-off-by: Xiaodong Ye <redacted>
* Merge errors into test_operation_info && address review comments

Signed-off-by: Xiaodong Ye <redacted>
* Address review comments

Signed-off-by: Xiaodong Ye <redacted>
* Address review comments

Signed-off-by: Xiaodong Ye <redacted>
* remove visitor nonsense

* remove visitor comment

Signed-off-by: Xiaodong Ye <redacted>
* Address review comments

Signed-off-by: Xiaodong Ye <redacted>
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Signed-off-by: Xiaodong Ye <redacted>
Co-authored-by: slaren <redacted>