fix compare_vec3 test: use D_TOL-compatible values, remove redundant section

tests/test_physics_utilities.cpp

@@ -207,8 +207,8 @@ SCENARIO("Rotation matrices", "[physics][utilities][rotation]") {
 SCENARIO("compare_vec3 utility", "[physics][utilities][compare]") {
     SECTION("equal vectors within tolerance") {
         const Vec3 a = {1.0, 2.0, 3.0};
-        const Vec3 b = {1.0001, 2.0001, 3.0001};
-        REQUIRE(compare_vec3(a, b, 1e-3));
+        const Vec3 b = {1.0 + 1e-13, 2.0 + 1e-13, 3.0 + 1e-13};
+        REQUIRE(compare_vec3(a, b, D_TOL));
     }
 
     SECTION("equal vectors exactly") {
@@ -222,10 +222,4 @@ SCENARIO("compare_vec3 utility", "[physics][utilities][compare]") {
         const Vec3 b = {2.0, 2.0, 3.0};
         REQUIRE(!compare_vec3(a, b, 0.5));
     }
-
-    SECTION("zero vector comparison") {
-        const Vec3 a = {0.0, 0.0, 0.0};
-        const Vec3 b = {0.0, 0.0, 0.0};
-        REQUIRE(compare_vec3(a, b, 0.0));
-    }
 }