Merge boxWithStdlib testData into box, delete BoxWithStdlib test

compiler/testData/codegen/box/when/kt5448.kt

@@ -0,0 +1,22 @@
+// WITH_RUNTIME
+
+class A
+
+class B(val items: Collection<A>)
+
+class C {
+    fun foo(p: Int) {
+        when (p) {
+            1 -> arrayListOf<Int>().add(1)
+        }
+    }
+
+    fun bar() = B(listOf<A>().map { it })
+}
+
+fun box(): String {
+    C().foo(1)
+    if (C().bar().items.isNotEmpty()) return "fail"
+
+    return "OK"
+}