Minor. Add regression test for KT-59051

FIR2IR generates correct IR, unlike PSI2IR.
 #KT-59051 Fixed

compiler/testData/codegen/box/delegation/doubleDelegationEqualsHashcode.kt

@@ -0,0 +1,22 @@
+// TARGET_BACKEND: JVM
+// IGNORE_BACKEND_K1: JVM, JVM_IR
+
+interface A {
+    override operator fun equals(other: Any?): Boolean
+    override fun hashCode(): Int
+}
+
+class AImpl : A {
+    override fun equals(other: Any?) = super.equals(other)
+    override fun hashCode() = super.hashCode()
+}
+
+interface B
+class BImpl : B
+
+class Impl : A by AImpl(), B by BImpl()
+
+fun box(): String {
+    Impl()
+    return "OK"
+}