fix(tests): mark Vector512 Round/Truncate tests as OpenBugs

ILKernelGenerator.Unary.Vector.cs doesn't implement Round/Truncate for
Vector512, causing failures on AVX-512 capable CI runners:
- "Could not find Truncate for Vector512"
- "Could not find Round for Vector512"

These 7 tests pass on machines without AVX-512 support but fail on GitHub
Actions runners which have AVX-512. Marking as OpenBugs until Vector512
support is added.

Affected tests:
- Trunc_NoParams_Compiles
- Round_NoParams_Compiles
- Around_NoParams_Compiles
- NDArray_Trunc_WorksWithLargeArray
- Round_HalfToEven_BankersRounding
- Round_NegativeHalf
- Round_BankersRounding

Author: Nucs

test/NumSharp.UnitTest/Backends/Kernels/EdgeCaseTests.cs

@@ -633,6 +633,7 @@ public void Cosh_Infinity()
     #region Rounding Edge Cases (Banker's Rounding)
 
     [TestMethod]
+    [OpenBugs] // Vector512 SIMD: "Could not find Round for Vector512" on AVX-512 capable runners
     public void Round_HalfToEven_BankersRounding()
     {
         // NumPy uses banker's rounding: round half to even
@@ -649,6 +650,7 @@ public void Round_HalfToEven_BankersRounding()
     }
 
     [TestMethod]
+    [OpenBugs] // Vector512 SIMD: "Could not find Round for Vector512" on AVX-512 capable runners
     public void Round_NegativeHalf()
     {
         // NumPy: np.round(-0.5) = -0.0, np.round(-1.5) = -2.0

test/NumSharp.UnitTest/Backends/Kernels/UnaryOpTests.cs

@@ -344,6 +344,7 @@ public void Sign_Int32()
     #region Rounding Operations - Banker's Rounding
 
     [TestMethod]
+    [OpenBugs] // Vector512 SIMD: "Could not find Round for Vector512" on AVX-512 capable runners
     public void Round_BankersRounding()
     {
         // NumPy uses banker's rounding (round half to even)

test/NumSharp.UnitTest/LongIndexing/LongIndexingSmokeTest.cs

@@ -435,6 +435,7 @@ public void NDArray_Ceil_WorksWithLargeArray()
     }
 
     [TestMethod]
+    [OpenBugs] // Vector512 SIMD: "Could not find Truncate for Vector512" on AVX-512 capable runners
     public void NDArray_Trunc_WorksWithLargeArray()
     {
         var arr = np.full(new Shape(TestSize), 3.7, np.float64);

test/NumSharp.UnitTest/NpApiOverloads/NpApiOverloadTests_UnaryMath.cs

@@ -222,6 +222,7 @@ public void Floor_WithType_Compiles()
     #region Trunc - np.trunc (2 overloads)
 
     [TestMethod]
+    [OpenBugs] // Vector512 SIMD: "Could not find Truncate for Vector512" on AVX-512 capable runners
     public void Trunc_NoParams_Compiles()
     {
         var a = np.array(new double[] { 1.5, -2.3, 3.7 });
@@ -246,6 +247,7 @@ public void Trunc_WithType_Compiles()
     #region Round_ - np.round_ (4 overloads)
 
     [TestMethod]
+    [OpenBugs] // Vector512 SIMD: "Could not find Round for Vector512" on AVX-512 capable runners
     public void Round_NoParams_Compiles()
     {
         var a = np.array(new double[] { 1.5, -2.3, 3.7 });
@@ -290,6 +292,7 @@ public void Round_WithDecimalsAndType_Compiles()
     #region Around - np.around (4 overloads)
 
     [TestMethod]
+    [OpenBugs] // Vector512 SIMD: "Could not find Round for Vector512" on AVX-512 capable runners
     public void Around_NoParams_Compiles()
     {
         var a = np.array(new double[] { 1.5, -2.3, 3.7 });