[K/N] Advance String(CharArray) deprecation level to ERROR

kotlin-native/backend.native/tests/runtime/basic/hash0.kt

@@ -22,5 +22,5 @@ import kotlin.test.*
     a[2] = 'l'
     a[3] = 'l'
     a[4] = 'o'
-    println("Hello".hashCode() == String(a, 0, 5).hashCode())
+    println("Hello".hashCode() == a.concatToString(0, 5).hashCode())
 }

kotlin-native/backend.native/tests/runtime/basic/tostring2.kt

@@ -15,5 +15,5 @@ import kotlin.test.*
         print(" ")
     }
     println()
-    println(String(array, 0, array.size))
+    println(array.concatToString(0, array.size))
 }