[IR] update testdata: print whole string concatenation at one line

compiler/testData/ir/irText/firProblems/SignatureClash.kt.txt

@@ -53,10 +53,7 @@ data class DataClass : Derived, Delegate {
   }
 
   override fun toString(): String {
-    return "DataClass(" + 
-"delegate=" + 
-<this>.#delegate + 
-")"
+    return "DataClass(" + "delegate=" + <this>.#delegate + ")"
   }
 
   override fun hashCode(): Int {