[Arm] Support INT16 ADD ops with TOSA reference model run

[Ninja91]

🚀 The feature, motivation and pitch

With this PR: #13653 we add support and test to 16a8w_quantize and lower add op. This fails at tosa reference model run with "Unsupported operation type or rank" and been marked as xfail. Enable run on TOSA ref model and enable this test.

Removed the xfails at https://github.com/pytorch/executorch/blob/main/backends/arm/test/ops/test_add.py#L283-L288 and for U85 and see

E RuntimeError: Compilation failed: Validation error: E Add Invalid arguments

Additionally,
cc: @gggekov , @digantdesai , @3l1

Alternatives

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Additional context

RFC (Optional)

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cc @digantdesai @freddan80 @per @zingo @oscarandersson8218

[gggekov]

This has been solved with #14645