Replaced deprecated inline classes with JvmInline value classes in tests

compiler/testData/codegen/box/inlineClasses/stringPlus.kt

@@ -1,8 +1,9 @@
-// !LANGUAGE: +InlineClasses
+// WITH_RUNTIME
 
 fun <T> foo(a: IC): T = a.value as T
 
-inline class IC(val value: String)
+@JvmInline
+value class IC(val value: String)
 
 fun box(): String {
     return foo<String>(IC("O")) + "K"