[FIR-TEST] Add new testdata generated after changes in previous commit

compiler/testData/diagnostics/tests/override/DuplicateMethod.fir.kt

@@ -0,0 +1,8 @@
+interface Some {
+    fun test()
+}
+
+class SomeImpl : Some  {
+    override fun test() {}
+    override fun test() {}
+}