Migrate boxInline tests to new multi-file framework

compiler/testData/codegen/boxInline/syntheticAccessors/protectedMembers.kt

@@ -0,0 +1,35 @@
+// FILE: 1.kt
+
+package test
+
+open class P {
+    protected open val FOO = "O"
+
+    protected open fun test() = "K"
+
+    inline fun protectedProp(): String {
+        return FOO
+    }
+
+    inline fun protectedFun(): String {
+        return test()
+    }
+}
+
+// FILE: 2.kt
+
+import test.*
+
+class A: P() {
+    override val FOO: String
+        get() = "fail"
+
+    override fun test(): String {
+        return "fail"
+    }
+}
+
+fun box() : String {
+    val p = P()
+    return p.protectedProp() + p.protectedFun()
+}