JVM IR: add test for complex generic diamond hierarchy

This is a test for KT-43832, which is fixed in the previous commit.

compiler/testData/codegen/box/traits/doubleGenericDiamond.kt

@@ -0,0 +1,34 @@
+// FILE: lib.kt
+
+var result = ""
+
+interface Left
+interface Right
+class Bottom : Left, Right
+
+interface A<T> {
+    fun f(): T? {
+        result = "A"
+        return null
+    }
+}
+
+interface B<T : Left> : A<T> {
+    override fun f(): T? {
+        result = "B"
+        return null
+    }
+}
+
+abstract class C<T> : A<T>
+
+abstract class D<T : Right> : C<T>()
+
+// FILE: box.kt
+
+class Z : D<Bottom>(), B<Bottom>
+
+fun box(): String {
+    Z().f()
+    return if (result == "B") "OK" else "Fail: $result"
+}