Migrate boxInline tests to new multi-file framework

compiler/testData/codegen/boxInline/enclosingInfo/objectInInlineFun.kt

@@ -0,0 +1,30 @@
+// FILE: 1.kt
+
+package test
+
+interface Z {
+    fun a(): String
+}
+
+inline fun test(crossinline z: () -> String) =
+        object : Z {
+            override fun a() = z()
+        }
+
+// FILE: 2.kt
+
+import test.*
+
+fun box(): String {
+    val res = test {
+        "OK"
+    }
+
+    val enclosingMethod = res.javaClass.enclosingMethod
+    if (enclosingMethod?.name != "box") return "fail 1: ${enclosingMethod?.name}"
+
+    val enclosingClass = res.javaClass.enclosingClass
+    if (enclosingClass?.name != "ObjectInInlineFun_1Kt") return "fail 2: ${enclosingClass?.name}"
+
+    return "OK"
+}