Migrate boxInline tests to new multi-file framework

compiler/testData/codegen/boxInline/reified/kt6988_2.kt

@@ -0,0 +1,21 @@
+// FILE: 1.kt
+
+package test
+
+
+public inline fun <reified T: Any> Any.inlineMeIfYouCan() : () -> Runnable = {
+    object : Runnable {
+        override fun run() {
+            T::class.java.newInstance()
+        }
+    }
+}
+
+// FILE: 2.kt
+
+import test.*
+
+fun box(): String {
+    "yo".inlineMeIfYouCan<StringBuilder>()().run()
+    return "OK"
+}