JS: use read-only AbstractList as a base class for read-only collection implementations.

js/js.libraries/src/core/regex.kt

@@ -17,7 +17,6 @@
 package kotlin.text
 
 import kotlin.text.js.*
-import java.util.*
 
 /**
  * Provides enumeration values to use to set regular expression options.

js/js.libraries/src/dom/DomJS.kt

@@ -4,7 +4,6 @@ import org.w3c.dom.*
 import org.w3c.dom.DOMTokenList
 import org.w3c.dom.HTMLCollection
 import org.w3c.dom.HTMLElement
-import java.util.*
 
 /** Searches for elements using the element name, an element ID (if prefixed with dot) or element class (if prefixed with #) */
 operator fun Document?.get(selector: String): List<Element> {