Math: fixed two typos in the test.

They resulted in fact that the test case didn't actually test anything.
Spotted by Clang.

src/Math/Test/DualComplexTest.cpp

@@ -126,7 +126,7 @@ void DualComplexTest::constructFromVector() {
 void DualComplexTest::constructCopy() {
     constexpr DualComplex a({-1.0f, 2.5f}, {3.0f, -7.5f});
     constexpr DualComplex b(a);
-    CORRADE_COMPARE(a, DualComplex({-1.0f, 2.5f}, {3.0f, -7.5f}));
+    CORRADE_COMPARE(b, DualComplex({-1.0f, 2.5f}, {3.0f, -7.5f}));
 }
 
 void DualComplexTest::isNormalized() {

src/Math/Test/DualQuaternionTest.cpp

@@ -124,7 +124,7 @@ void DualQuaternionTest::constructFromVector() {
 void DualQuaternionTest::constructCopy() {
     constexpr DualQuaternion a({{1.0f, 2.0f, -3.0f}, -3.5f}, {{4.5f, -7.0f, 2.0f}, 1.0f});
     constexpr DualQuaternion b(a);
-    CORRADE_COMPARE(a, DualQuaternion({{1.0f, 2.0f, -3.0f}, -3.5f}, {{4.5f, -7.0f, 2.0f}, 1.0f}));
+    CORRADE_COMPARE(b, DualQuaternion({{1.0f, 2.0f, -3.0f}, -3.5f}, {{4.5f, -7.0f, 2.0f}, 1.0f}));
 }
 
 void DualQuaternionTest::isNormalized() {