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

compiler/testData/diagnostics/tests/override/ToAbstractMembersFromSuper-kt1996.fir.kt

@@ -0,0 +1,11 @@
+// http://youtrack.jetbrains.com/issue/KT-1996
+
+interface Foo {
+    fun foo(): Unit
+}
+
+interface Bar {
+    fun foo(): Unit
+}
+
+class Baz : Foo, Bar