JS: replace all usages of @native annotation with external modifier, in tests, stdlib, etc

libraries/tools/kotlin-stdlib-gen/src/templates/SpecialJS.kt

@@ -255,7 +255,7 @@ fun specialJS(): List<GenericFunction> {
     templates add f("sort(comparison: (T, T) -> Int)") {
         only(ArraysOfObjects, ArraysOfPrimitives)
         exclude(PrimitiveType.Boolean)
-        annotations("@native")
+        external(true)
         returns("Unit")
         doc { "Sorts the array in-place according to the order specified by the given [comparison] function." }
         body { "noImpl" }

libraries/tools/kotlin-stdlib-gen/src/templates/engine/Engine.kt

@@ -147,6 +147,7 @@ class GenericFunction(val signature: String, val keyword: String = "fun") {
     val returns = FamilyProperty<String>()
     val operator = FamilyProperty<Boolean>()
     val infix = FamilyProperty<Boolean>()
+    val external = FamilyProperty<Boolean>()
     val body = object : FamilyProperty<String>() {
         override fun onKeySet(key: Family) = include(key)
     }
@@ -410,6 +411,8 @@ class GenericFunction(val signature: String, val keyword: String = "fun") {
         }
 
         builder.append("public ")
+        if (external[f] == true)
+            builder.append("external ")
         if (inline[f]?.isInline() == true)
             builder.append("inline ")
         if (infix[f] == true)