Add support for CASE_INSENSITIVE_ORDER in JS and common

#KT-18067

libraries/stdlib/common/src/kotlin/TextH.kt

@@ -187,6 +187,16 @@ expect fun CharSequence.regionMatches(
 ): Boolean
 
 
+/**
+ * A Comparator that orders strings ignoring character case.
+ *
+ * Note that this Comparator does not take locale into account,
+ * and will result in an unsatisfactory ordering for certain locales.
+ */
+@SinceKotlin("1.2")
+public expect val String.Companion.CASE_INSENSITIVE_ORDER: Comparator<String>
+
+
 /**
  * Returns `true` if the contents of this string is equal to the word "true", ignoring case, and `false` otherwise.
  */