Support String factory functions

runtime/src/main/kotlin/kotlin/text/Strings.kt

@@ -44,3 +44,14 @@ public actual fun CharSequence.repeat(n: Int): String {
         }
     }
 }
+
+/**
+ * Converts the characters in the specified array to a string.
+ */
+// external fun fromCharArray(array: CharArray, start: Int, size: Int) : String
+public actual fun String(chars: CharArray): String = fromCharArray(chars, 0, chars.size)
+
+/**
+ * Converts the characters from a portion of the specified array to a string.
+ */
+public actual fun String(chars: CharArray, offset: Int, length: Int): String = fromCharArray(chars, offset, length)