Fix JS completion tests: remove unneeded imports, take care about type aliases looking different in completion.

idea/idea-completion/testData/basic/common/extensions/JavaTypeExtension.kt

@@ -1,11 +1,9 @@
-import java.util.* // temporary until typealiases for collection are introduced in JVM
-
 fun <T> Iterable<T>.first() : T? {
     return this.iterator()?.next()
 }
 
 fun main(args : Array<String>) {
-    val test = HashSet<Int>()
+    val test = HashSet<Int>() // aliased in JVM to java.util.HashSet
     test.<caret>
 }