[Type] UnitTest: use EXPECT_DOUBLE_EQ as advised for Matrix:trace() test

[fredroy]

Since always (?), on my mac, when running the Sofa.Type_test unittests, one test was failing:
[ FAILED ] MatSymTest/1.trace, where TypeParam = sofa::MatSymTestParameterPack<3u,double>
due to :

The difference between expectedTrace and sofa::type::trace(m_symmetricMatrix) is 8.8817841970012523e-16, where
expectedTrace evaluates to 7.3017516772499684,
sofa::type::trace(m_symmetricMatrix) evaluates to 7.3017516772499675.
The abs_error parameter testing::NumericTest<Real>::epsilon() evaluates to 2.2204460492503131e-16 which is smaller than the minimum distance between doubles for numbers of this magnitude which is 8.8817841970012523e-16, thus making this EXPECT_NEAR check equivalent to EXPECT_EQUAL. Consider using EXPECT_DOUBLE_EQ instead.

I guess this fail was depending greatly one the platform/compiler/cpu type.

After setting this, no fail anymore.

---

By submitting this pull request, I acknowledge that
I have read, understand, and agree SOFA Developer Certificate of Origin (DCO).

---

Reviewers will merge this pull-request only if

• it builds with SUCCESS for all platforms on the CI.
• it does not generate new warnings.
• it does not generate new unit test failures.
• it does not generate new scene test failures.
• it does not break API compatibility.
• it is more than 1 week old (or has fast-merge label).