Migrate boxInline tests to new multi-file framework

compiler/testData/codegen/boxInline/reified/kt9637_2.kt

@@ -0,0 +1,22 @@
+// FILE: 1.kt
+
+package test
+
+import kotlin.reflect.KClass
+
+inline fun <reified T : Any> injectFnc(): KClass<T> = {
+    T::class
+} ()
+
+public class Box
+
+// FILE: 2.kt
+
+import test.*
+
+fun box(): String {
+    val boxClass = injectFnc<Box>()
+    if (boxClass != Box::class) return "fail 1"
+
+    return "OK"
+}