[K/N] Internalize RegexOption.value/mask properties

As a part of efforts to stabilize K/N stdlib.

libraries/stdlib/native-wasm/src/kotlin/text/Regex.kt

@@ -7,13 +7,7 @@ package kotlin.text
 
 import kotlin.text.regex.*
 
-@PublishedApi
-internal interface FlagEnum {
-    val value: Int
-    val mask: Int
-}
-
-private fun Iterable<FlagEnum>.toInt(): Int = this.fold(0, { value, option -> value or option.value })
+private fun Iterable<RegexOption>.toInt(): Int = this.fold(0, { value, option -> value or option.value })
 
 private fun fromInt(value: Int): Set<RegexOption> =
         RegexOption.values().filterTo(mutableSetOf<RegexOption>()) { value and it.mask == it.value  }
@@ -21,7 +15,7 @@ private fun fromInt(value: Int): Set<RegexOption> =
 /**
  * Provides enumeration values to use to set regular expression options.
  */
-public actual enum class RegexOption(override val value: Int, override val mask: Int = value) : FlagEnum {
+public actual enum class RegexOption(internal val value: Int, internal val mask: Int = value) {
     // common
 
     /** Enables case-insensitive matching. Case comparison is Unicode-aware. */
@@ -96,10 +90,10 @@ public actual class Regex internal constructor(internal val nativePattern: Patte
     actual constructor(pattern: String): this(Pattern(pattern))
 
     /** Creates a regular expression from the specified [pattern] string and the specified single [option].  */
-    actual constructor(pattern: String, option: RegexOption): this(Pattern(pattern, ensureUnicodeCase(option.value)))
+    actual constructor(pattern: String, option: RegexOption): this(Pattern(pattern, option.value))
 
     /** Creates a regular expression from the specified [pattern] string and the specified set of [options].  */
-    actual constructor(pattern: String, options: Set<RegexOption>): this(Pattern(pattern, ensureUnicodeCase(options.toInt())))
+    actual constructor(pattern: String, options: Set<RegexOption>): this(Pattern(pattern, options.toInt()))
 
 
     /** The pattern string of this regular expression. */
@@ -142,9 +136,6 @@ public actual class Regex internal constructor(internal val nativePattern: Patte
 
             return result.toString()
         }
-
-        // TODO: Remove
-        private fun ensureUnicodeCase(flags: Int) = flags
     }
 
     private fun doMatch(input: CharSequence, mode: Mode): MatchResult? {