Merge stored empty lists and sets to singe object

core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/lazy/descriptors/LazyJavaMemberScope.kt

@@ -100,7 +100,7 @@ public abstract class LazyJavaMemberScope(
             }
         }
 
-        ArrayList(functions)
+        functions.toReadOnlyList()
     }
 
     data class MethodSignatureData(
@@ -237,8 +237,7 @@ public abstract class LazyJavaMemberScope(
 
         computeNonDeclaredProperties(name, properties)
 
-        properties.trimToSize()
-        properties
+        properties.toReadOnlyList()
     }
 
     private fun resolveProperty(field: JavaField): PropertyDescriptor {
@@ -303,7 +302,7 @@ public abstract class LazyJavaMemberScope(
     override fun getOwnDeclaredDescriptors() = getAllDescriptors()
     override fun getAllDescriptors() = _allDescriptors()
 
-    private fun computeAllDescriptors(): MutableCollection<DeclarationDescriptor> {
+    private fun computeAllDescriptors(): List<DeclarationDescriptor> {
         val result = LinkedHashSet<DeclarationDescriptor>()
 
         for (name in getAllClassNames()) {
@@ -324,7 +323,7 @@ public abstract class LazyJavaMemberScope(
 
         addExtraDescriptors(result)
 
-        return ArrayList(result)
+        return result.toReadOnlyList()
     }
 
     protected open fun addExtraDescriptors(result: MutableSet<DeclarationDescriptor>) {