Tests for abstract functions with default arguments

compiler/testData/codegen/box/defaultArguments/function/abstractClass.kt

@@ -0,0 +1,16 @@
+abstract class Base {
+    abstract fun foo(a: String = "abc"): String
+}
+
+class Derived: Base() {
+    override fun foo(a: String): String {
+        return a
+    }
+}
+
+fun box(): String {
+    val result = Derived().foo()
+    if (result != "abc") return "Fail: $result"
+
+    return "OK"
+}

compiler/testData/codegen/box/defaultArguments/function/trait.kt

@@ -0,0 +1,14 @@
+trait Base {
+    fun bar(a: String = "abc"): String = a + " from trait"
+}
+
+class Derived: Base {
+    override fun bar(a: String): String = a + " from class"
+}
+
+fun box(): String {
+    val result = Derived().bar()
+    if (result != "abc from class") return "Fail: $result"
+
+    return "OK"
+}