Handle methods descriptor clash in data class

1. Extension functions declared in data classes are generated earlier by `generateMembersDeclaredInClassBody`
2. Extension functions fake override from parent class are generated earlier by `generateFakeOverrideMemberDeclarations`

So it is safe to filter out extension functions inside `generateAdditionalMembersForDataClass`

 #KT-49715
 #KT-51798

compiler/backend-common/src/org/jetbrains/kotlin/backend/common/CodegenUtil.kt

@@ -141,7 +141,8 @@ object CodegenUtil {
                         function.modality != Modality.FINAL &&
                         areParametersOk(function.valueParameters) &&
                         function.returnType != null &&
-                        isReturnTypeOk(function.returnType!!)
+                        isReturnTypeOk(function.returnType!!) &&
+                        function.extensionReceiverParameter == null
                     }