Migrate boxInline tests to new multi-file framework

compiler/testData/codegen/boxInline/complex/closureChain.kt

@@ -0,0 +1,21 @@
+// FILE: 1.kt
+
+class Inline() {
+
+    inline fun foo(closure1 : (l: Int) -> String, param: Int, closure2: String.() -> Int) : Int {
+        return closure1(param).closure2()
+    }
+}
+
+// FILE: 2.kt
+
+fun test1(): Int {
+    val inlineX = Inline()
+    return inlineX.foo({ z: Int -> "" + z}, 25, fun String.(): Int = this.length)
+}
+
+fun box(): String {
+    if (test1() != 2) return "test1: ${test1()}"
+
+    return "OK"
+}