compare-commits.sh: support both llama-bench and test-backend-ops (#14392)

compare-commits.sh: support both llama-bench and test-backend-ops (#14392)

* compare-commits.sh: support both llama-bench and test-backend-ops

Signed-off-by: Xiaodong Ye <redacted>
* Speed up the build by specifying -j 12

Signed-off-by: Xiaodong Ye <redacted>
* Remove build_number from test-backend-ops db

Signed-off-by: Xiaodong Ye <redacted>
* Apply suggestion from @JohannesGaessler

Co-authored-by: Johannes Gäßler <redacted>
* Refine tool selection logic

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