message: Fix poplar_algebraic_simplifier_test
  Summary:
  This test was previously not enabled and there is a slight
  difference between v1 and v2
  Test Plan: poplar_algebraic_simplifier_test passes
  Reviewers: #tensorflow, anthonyb
  Subscribers: anthonyb
diff: @@ -1252,7 +1252,7 @@ TEST_F(PoplarAlgebraicSimplifierTest, PowExp) {
  GmockMatch(m::Exp(m::Multiply(m::Parameter(0), m::Parameter(1)))));
  }
  -// Test that ln(pow(A, B)) is simplified to ln(A)*B
  +// Test that ln(pow(A, B)) is simplified to ln(abs(A))*B
  TEST_F(PoplarAlgebraicSimplifierTest, LnPow) {
  auto m = CreateNewVerifiedModule();
  Shape r0f32 = ShapeUtil::MakeShape(F32, {});
  @@ -1274,9 +1274,9 @@ TEST_F(PoplarAlgebraicSimplifierTest, LnPow) {
  PoplarAlgebraicSimplifier simplifier;
  ASSERT_TRUE(simplifier.Run(m.get()).ValueOrDie());
  - EXPECT_THAT(
  - computation->root_instruction(),
  - GmockMatch(m::Multiply(m::Log(m::Parameter(0)), m::Parameter(1))));
  + EXPECT_THAT(computation->root_instruction(),
  + GmockMatch(m::Multiply(m::Log(m::Abs(m::Parameter(0))),
  + m::Parameter(1))));
  }
  // Test that ln(exp(A)) is simplified to A
  