Add more test cases

src/tests/JIT/Regression/JitBlue/Runtime_71375/Runtime_71375.cs

@@ -24,4 +24,58 @@ public static bool Problem()
     {
         return VarArgs(0, 0, 0, 0, 0, 0, Vector128<int>.AllBitsSet, __arglist()) != -1;
     }
+
+    [Fact]
+    public static int TestEntryPoint2()
+    {
+        if (Case2())
+            return 101;
+        return 100;
+    }
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    static int VarArgs2(int arg1, int arg2, int arg3, int arg4, int arg5, Vector128<int> vecArg, __arglist) => vecArg.GetElement(0);
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool Case2()
+    {
+        // vector is not split: it is passed in registers x6, x7
+        return VarArgs2(0, 0, 0, 0, 0, Vector128<int>.AllBitsSet, __arglist()) != -1;
+    }
+
+    [Fact]
+    public static int TestEntryPoint3()
+    {
+        if (Case3())
+            return 101;
+        return 100;
+    }
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    static int VarArgs3(int arg1, int arg2, int arg3, int arg4, int arg5, int arg6, int arg7, Vector128<int> vecArg, __arglist) => vecArg.GetElement(0);
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool Case3()
+    {
+        // vector is not split: it is passed entirely on the stack
+        return VarArgs3(0, 0, 0, 0, 0, 0, 0, Vector128<int>.AllBitsSet, __arglist()) != -1;
+    }
+
+    [Fact]
+    public static int TestEntryPoint4()
+    {
+        if (Case4())
+            return 101;
+        return 100;
+    }
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    static int VarArgs4(int arg1, object arg2, int arg3, object arg4, int arg5, object arg6, Vector128<int> splitArg, __arglist) => splitArg.GetElement(0);
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool Case4()
+    {
+        // Spit the vector but also pass some object types so the GC needs to know about them.
+        return VarArgs4(0, new object(), 0, new object(), 0, new object(), Vector128<int>.AllBitsSet, __arglist()) != -1;
+    }
 }