code: def test_builder_to_backend_stress(
      self, compute_unit, backend, shapes
  ):
      shape_x, shape_y = shapes
      x_val = np.random.rand(*shape_x)
      y_val = np.random.rand(*shape_y)
      input_placeholders = {
          "x": mb.placeholder(shape=x_val.shape),
          "y": mb.placeholder(shape=y_val.shape),
      }
      input_values = {"x": x_val, "y": y_val}
  
      def build(x, y):
          return [
              mb.matmul(x=x, y=y, transpose_x=False, transpose_y=False)
          ]
  
      expected_outputs = [np.matmul(x_val, y_val)]
      expected_output_types = [
          o.shape[:] + (types.fp32,) for o in expected_outputs
      ]
  
      run_compare_builder(
          build,
          input_placeholders,
          input_values,
          expected_output_types,
          expected_outputs,
          compute_unit=compute_unit,
          backend=backend,
      )
  
imports: import itertools
  import platform
  import numpy
  import pytest
  import coremltools
  from coremltools.converters.mil.mil import Builder
  from coremltools.converters.mil.mil import get_new_symbol, types
  from coremltools.converters.mil.mil.ops.tests.iOS14 import backends
  from coremltools.converters.mil.mil.ops.tests.testing_utils import run_compare_builder
  from coremltools.converters.mil.mil.types import builtin_to_string, nptype_from_builtin
  from coremltools.converters.mil.testing_reqs import compute_units
  from coremltools.converters.mil.testing_utils import random_gen, ssa_fn
label_desc: Use image node_id 3 for calling the TestMatMul obj's underlying member method code with example usage: obj.test_builder_to_backend_stress(compute_unit, backend, shapes) and returns: list