Fixed bug in DefaultArgs lowering with vararg arguments + tests

backend.native/tests/build.gradle

@@ -362,6 +362,16 @@ task function_defaults_from_fake_override(type: RunKonanTest) {
     source = "codegen/function/defaultsFromFakeOverride.kt"
 }
 
+task function_defaults_with_vararg1(type: RunKonanTest) {
+    goldValue = "Hello , Correct!\nHello World, Correct!\n , Correct!\n"
+    source = "codegen/function/defaultsWithVarArg1.kt"
+}
+
+task function_defaults_with_vararg2(type: RunKonanTest) {
+    goldValue = "1\n2\n42\n"
+    source = "codegen/function/defaultsWithVarArg2.kt"
+}
+
 task sum_3const(type: RunKonanTest) {
     source = "codegen/function/sum_3const.kt"
 }

backend.native/tests/codegen/function/defaultsWithVarArg1.kt

@@ -0,0 +1,21 @@
+package codegen.function.defaultsWithVarArg1
+
+import kotlin.test.*
+
+fun foo(s: String = "", vararg args: Any) {
+    if (args == null) {
+        println("Failed!")
+    } else {
+        print("$s ")
+        args.forEach {
+            print("$it")
+        }
+        println(", Correct!")
+    }
+}
+
+@Test fun runTest() {
+    foo("Hello")
+    foo("Hello", "World")
+    foo()
+}

backend.native/tests/codegen/function/defaultsWithVarArg2.kt

@@ -0,0 +1,12 @@
+package codegen.function.defaultsWithVarArg2
+
+import kotlin.test.*
+
+fun foo(vararg arr: Int = intArrayOf(1, 2)) {
+    arr.forEach { println(it) }
+}
+
+@Test fun runTest() {
+    foo()
+    foo(42)
+}