Add regression tests for obsolete issues

#KT-50909
 #KT-50974
 #KT-51888

compiler/testData/codegen/box/jvm8/defaults/nonDefaultInheritance/diamondWithJava.kt

@@ -0,0 +1,26 @@
+// TARGET_BACKEND: JVM_IR
+// JVM_TARGET: 1.8
+// MODULE: lib
+// !JVM_DEFAULT_MODE: all
+// FILE: P.java
+
+public interface P {
+    default String test() {
+        return "OK";
+    }
+}
+
+// FILE: kotlin.kt
+
+abstract class A : P
+
+interface B : P
+
+// MODULE: main(lib)
+// !JVM_DEFAULT_MODE: disable
+// FILE: main.kt
+abstract class C : A(), P, B
+
+fun box(): String {
+    return object : C() {}.test()
+}