message: fix failing test
  Test Plan: all tests pass
  Reviewers: #tensorflow, davidn
diff: @@ -228,7 +228,7 @@ class FrontendAttributesTest(test_util.TensorFlowTestCase):
  with ipu.scopes.partials_type(np.float32):
  pa, pb, fd = _createInputs([2, 2], np.float16)
  output = math_ops.matmul(pa, pb)
  - outputs[output] = ("poplin::ReduceAdd<half,float", fd)
  + outputs[output] = ("poplin::ConvPartial*<half,float", fd)
  with ipu.scopes.partials_type(np.float16):
  pa, pb, fd = _createInputs([3, 3], np.float16)
  output = math_ops.matmul(pa, pb)
  @@ -236,7 +236,7 @@ class FrontendAttributesTest(test_util.TensorFlowTestCase):
  with ipu.scopes.partials_type(np.float32):
  pa, pb, fd = _createInputs([4, 4], np.float16)
  output = math_ops.matmul(pa, pb)
  - outputs[output] = ("poplin::ReduceAdd<half,float", fd)
  + outputs[output] = ("poplin::ConvPartial*<half,float", fd)
  pa, pb, fd = _createInputs([5, 5], np.float16)
  output = math_ops.matmul(pa, pb)
  outputs[output] = ("poplin::ConvPartial*<half,half", fd)
  