Fix System.Object.GetCustomAttributes() returning extra internal attributes on Mono (#117864)

* Fix System.Object GetCustomAttributes inherit parameter inconsistency

* Use do-while loop to include System.Object attributes

Author: medhatiwari

src/coreclr/System.Private.CoreLib/src/System/Reflection/RuntimeCustomAttributeData.cs

@@ -1270,12 +1270,12 @@ internal static object[] GetCustomAttributes(RuntimeType type, RuntimeType caTyp
             for (int i = 0; i < pcas.Count; i++)
                 result.Add(pcas[i]);
 
-            while (type != (RuntimeType)typeof(object) && type != null)
+            do
             {
                 AddCustomAttributes(ref result, type.GetRuntimeModule(), type.MetadataToken, caType, mustBeInheritable, result);
                 mustBeInheritable = true;
                 type = (type.BaseType as RuntimeType)!;
-            }
+            } while (type != (RuntimeType)typeof(object) && type != null);
 
             object[] typedResult = CreateAttributeArrayHelper(caType, result.Count);
             for (int i = 0; i < result.Count; i++)

src/libraries/System.Runtime/tests/System.Reflection.Tests/CustomAttributeTests.cs

@@ -275,5 +275,14 @@ public void BoxedEnumAttributes()
             Assert.Equal(typeof(EnumForArrays[]), att.B3.GetType());
             Assert.Equal(EnumForArrays.Two, ((EnumForArrays[])att.B3)[0]);
         }
+
+        [Fact]
+        public void SystemObject_GetCustomAttributes_InheritanceConsistency()
+        {
+            Type objectType = typeof(object);
+            object[] attributesWithoutInherit = objectType.GetCustomAttributes(inherit: false);
+            object[] attributesWithInherit = objectType.GetCustomAttributes(inherit: true);
+            Assert.Equal(attributesWithoutInherit.Length, attributesWithInherit.Length);
+        }
     }
 }