message: [unittest] Fix scalar unit test.
  The test was using ASSERT_EQ instead of ASSERT_STREQ which meant we were
  comparing string addresses instead of the actual string. This caused the
  test to fail with with the sanitizers enabled.
diff: @@ -288,13 +288,13 @@ TEST(ScalarTest, Scalar_512) {
  ASSERT_TRUE(Z.IsZero());
  Scalar S(APInt(512, 2000));
  - EXPECT_EQ(S.GetTypeAsCString(), "int512_t");
  - EXPECT_EQ(S.GetValueTypeAsCString(Scalar::e_sint512), "int512_t");
  + ASSERT_STREQ(S.GetTypeAsCString(), "int512_t");
  + ASSERT_STREQ(S.GetValueTypeAsCString(Scalar::e_sint512), "int512_t");
  ASSERT_TRUE(S.MakeUnsigned());
  EXPECT_EQ(S.GetType(), Scalar::e_uint512);
  - EXPECT_EQ(S.GetTypeAsCString(), "unsigned int512_t");
  - EXPECT_EQ(S.GetValueTypeAsCString(Scalar::e_uint512), "uint512_t");
  + ASSERT_STREQ(S.GetTypeAsCString(), "unsigned int512_t");
  + ASSERT_STREQ(S.GetValueTypeAsCString(Scalar::e_uint512), "uint512_t");
  EXPECT_EQ(S.GetByteSize(), 64U);
  ASSERT_TRUE(S.MakeSigned());
  