Testbench update axpy kernel

[n0thingNoob]

The original kernel emits arguments via the YAML output. To simplify testing, I slightly modified it by moving the constant values into the kernel.

[Copilot]

Pull request overview

This PR simplifies the axpy kernel test by moving constant values (N=16, A=3) from function parameters into the kernel itself. This change reduces the complexity of the test setup by eliminating the need to handle parameter values through YAML output files.

Changes:

• Added a new bash script to sync e2e test outputs to the Zeonica_Testbench submodule
• Modified the axpy kernel to use hardcoded constants instead of parameters, reducing the function signature from 4 parameters to 2
• Updated the MLIR test expectations to reflect the new kernel signature and simplified compiled output (II reduced from 6 to 5)

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
tools/sync_e2e_outputs_to_zeonica_testbench.sh	New utility script to synchronize e2e test outputs (DFG, YAML, ASM files) to the Zeonica_Testbench submodule
test/benchmark/axpy/axpy_int.cpp	Simplified kernel signature by moving N and A constants into the function body
test/e2e/axpy/axpy_kernel.mlir	Updated test expectations to match new kernel signature with 2 parameters instead of 4, reflecting improved compilation metrics

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