Merge boxWithStdlib testData into box, delete BoxWithStdlib test

compiler/testData/codegen/box/defaultArguments/kt6382.kt

@@ -0,0 +1,16 @@
+// WITH_RUNTIME
+
+fun box(): String {
+    return if (A().run() == "Aabc") "OK" else "fail"
+}
+
+public class A {
+    fun run() =
+            with ("abc") {
+                show()
+            }
+
+    private fun String.show(p: Boolean = false): String = getName() + this
+
+    private fun getName() = "A"
+}