Minor, move builtins serializer test data

compiler/testData/serialization/builtinsSerializer/annotationArguments/string.txt

@@ -0,0 +1,19 @@
+package test
+
+test.JustString(string = "kotlin": kotlin.String) test.StringArray(stringArray = {}: kotlin.Array<kotlin.String>) internal final class C1 {
+    public constructor C1()
+}
+
+test.StringArray(stringArray = {"java", ""}: kotlin.Array<kotlin.String>) internal final class C2 {
+    public constructor C2()
+}
+
+internal final annotation class JustString : kotlin.Annotation {
+    public constructor JustString(/*0*/ string: kotlin.String)
+    internal final val string: kotlin.String
+}
+
+internal final annotation class StringArray : kotlin.Annotation {
+    public constructor StringArray(/*0*/ stringArray: kotlin.Array<kotlin.String>)
+    internal final val stringArray: kotlin.Array<kotlin.String>
+}