CVS-165537 Minor fixes to partially enable contrib op tests

[RajeevSekar]

Scope of the ticket was for the following 4 contrib ops:

onnxruntime/test/contrib_ops/embed_layer_norm_op_test.cc
onnxruntime/test/contrib_ops/matmul_4bits_test.cc
onnxruntime/test/contrib_ops/dynamic_quantize_matmul_test.cc
onnxruntime/test/contrib_ops/fused_matmul_op_test.cc

Fixes:

1. dynamic_quantize: no change because absolute error between OV and expected is too high, so test remains skipped
2. embed_layer: OpenVINO EP only supports 2 outputs for EmbedLayerNormalization, skip only when 3rd output (embedding_sum) is requested
3. fused_matmul: Disable OpenVINO for scale (alpha != 1.0) and transBatch cases due to OV compilation errors., other than that run with OVEP.
4. matmul_4bits: error thresholds added for float_32 cases and compile time skipping removed

[Copilot]

Pull request overview

This PR updates several contrib-op unit tests to run more broadly with the OpenVINO Execution Provider (where supported), while keeping known-incompatible scenarios excluded to avoid OpenVINO compilation/runtime failures.

Changes:

• Enable MatMulNBits float32 test coverage with OpenVINO by adding explicit error tolerances and removing the USE_OPENVINO compile-time skip.
• Update EmbedLayerNormalization tests to only exclude OpenVINO when the optional 3rd output (embedding_sum) is requested.
• Refine FusedMatMul test execution provider exclusions so OpenVINO is only excluded for alpha != 1.0 and transBatch cases.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
onnxruntime/test/contrib_ops/matmul_4bits_test.cc	Adds default tolerances for float32 path and removes OpenVINO compile-time gating for float32 accuracy tests.
onnxruntime/test/contrib_ops/fused_matmul_op_test.cc	Makes OpenVINO exclusion conditional (scale/transBatch only) while still excluding other unsupported EPs.
onnxruntime/test/contrib_ops/embed_layer_norm_op_test.cc	Allows OpenVINO to run when only 2 outputs are used; excludes it when the 3rd output is requested.

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[preetha-intel]

LGTM