Use non-allowed actual defaults in backends to workaround compiler exception

It's difficult to fix KT-22818 until the IR comes along, so we're
providing a workaround where one can disable the
ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS error and provide default values
in the actual function, to avoid exception from the backend.

 #KT-22818

compiler/testData/codegen/box/multiplatform/defaultArguments/bothInExpectAndActual.kt

@@ -0,0 +1,28 @@
+// !LANGUAGE: +MultiPlatformProjects
+// IGNORE_BACKEND: JVM_IR, JS_IR
+// FILE: common.kt
+
+public expect fun <T> Array<out T>.copyInto(
+    destination: Array<T>, destinationOffset: Int = 0, startIndex: Int = 0, endIndex: Int = size
+): Array<T>
+
+// FILE: platform.kt
+
+// This test should be updated once KT-22818 is fixed; default values are not allowed in the actual function
+@Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
+public actual fun <T> Array<out T>.copyInto(
+    destination: Array<T>, destinationOffset: Int = 42, startIndex: Int = 43, endIndex: Int = size + 44
+): Array<T> {
+    destination as Array<Int>
+    destination[0] = destinationOffset
+    destination[1] = startIndex
+    destination[2] = endIndex
+    return destination
+}
+
+fun box(): String {
+    val a = Array<Int>(3) { it }
+    val result = a.copyInto(a)
+    return if (result[0] == 42 && result[1] == 43 && result[2] == 47) "OK"
+           else "Fail: ${result[0]} ${result[1]} ${result[2]}"
+}

compiler/testData/codegen/box/multiplatform/defaultArguments/bothInExpectAndActual2.kt

@@ -0,0 +1,30 @@
+// !LANGUAGE: +MultiPlatformProjects
+// IGNORE_BACKEND: JVM_IR, JS_IR
+// FILE: common.kt
+
+expect interface I {
+    fun test(source: String = "expect")
+}
+
+expect interface J : I
+
+// FILE: platform.kt
+
+actual interface I {
+    // This test should be updated once KT-22818 is fixed; default values are not allowed in the actual function
+    @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
+    actual fun test(source: String = "actual")
+}
+
+actual interface J : I {
+    override fun test(source: String) {
+        if (source != "actual") throw AssertionError(source)
+    }
+}
+
+class K : J
+
+fun box(): String {
+    K().test()
+    return "OK"
+}