Migrate boxInline tests to new multi-file framework

compiler/testData/codegen/boxInline/reified/kt6990.kt

@@ -0,0 +1,22 @@
+// FILE: 1.kt
+
+package test
+
+public inline fun <reified T : Any> inlineMeIfYouCan(): String? =
+        {
+            f {
+                T::class.java.getName()
+            }
+        }()
+
+inline fun f(x: () -> String) = x()
+
+// FILE: 2.kt
+
+import test.*
+
+class OK
+
+fun box(): String {
+    return inlineMeIfYouCan<OK>()!!
+}