message: Change assert to expect, update comments
diff: @@ -2596,9 +2596,8 @@ ENTRY main {
  }
  TEST_P(HloEvaluatorTest, DontFailOnCall) {
  - // The following test used to trigger unimplemented error instead of returning
  - // false. This was due to HandleCall in HloEvaluator using ConsumeValueOrDie
  - // to get a literal value, however this is not possible with RNG.
  + // RNG triggers unimplemented error within HandleCall, and we verify that the
  + // Evaluator does fail in such case.
  const string hlo_text = R"(
  HloModule DontFailOnCall
  @@ -2614,13 +2613,12 @@ ENTRY main {
  )";
  ParseAndVerifyModule(hlo_text);
  auto statusor = Evaluate();
  - ASSERT_FALSE(statusor.status().ok());
  + EXPECT_FALSE(statusor.status().ok());
  }
  TEST_P(HloEvaluatorTest, DontFailOnFusion) {
  - // The following test used to trigger unimplemented error instead of returning
  - // false. This was due to HandleFusion in HloEvaluator using ConsumeValueOrDie
  - // to get a literal value, however this is not possible with RNG.
  + // RNG triggers unimplemented error within HandleFusion, and we verify that
  + // the Evaluator does fail in such case.
  const string hlo_text = R"(
  HloModule DontFailOnFusion
  @@ -2636,14 +2634,12 @@ ENTRY main {
  )";
  ParseAndVerifyModule(hlo_text);
  auto statusor = Evaluate();
  - ASSERT_FALSE(statusor.status().ok());
  + EXPECT_FALSE(statusor.status().ok());
  }
  TEST_P(HloEvaluatorTest, DontFailOnConditional) {
  - // The following test used to trigger unimplemented error instead of returning
  - // false. This was due to HandleConditional in HloEvaluator using
  - // ConsumeValueOrDie to get a literal value, however this is not possible
  - // with RNG.
  + // RNG triggers unimplemented error within HandleConditional, and we verify
  + // that the Evaluator does fail in such case.
  const string hlo_text = R"(
  HloModule DontFailOnConditional
  @@ -2674,7 +2670,7 @@ ENTRY main (pred: pred[]) -> f32[]{
  ParseAndVerifyModule(hlo_text);
  Literal arg = LiteralUtil::CreateR0<bool>(false);
  auto statusor = Evaluate({&arg});
  - ASSERT_FALSE(statusor.status().ok());
  + EXPECT_FALSE(statusor.status().ok());
  }
  INSTANTIATE_TEST_CASE_P(HloEvaluatorTest_Instantiation, HloEvaluatorTest,
  