[es6] Map/Set size getter should have "get size" name

src/collection-iterator.js

Index: src/collection-iterator.js
diff --git a/src/collection-iterator.js b/src/collection-iterator.js
index c99947b47caaac738d4fe13ac9f4d3c061da0022..d2e0af93c01e61c5f43af3119bf9de411123e2c3 100644
--- a/src/collection-iterator.js
+++ b/src/collection-iterator.js
@@ -80,7 +80,7 @@ InstallFunctions(SetIterator.prototype, DONT_ENUM, [
   'next', SetIteratorNextJS
 ]);
 
-%FunctionSetName(SetIteratorSymbolIterator, '[Symbol.iterator]');
+SetFunctionName(SetIteratorSymbolIterator, symbolIterator);
 %AddNamedProperty(SetIterator.prototype, symbolIterator,
     SetIteratorSymbolIterator, DONT_ENUM);
 %AddNamedProperty(SetIterator.prototype, symbolToStringTag,
@@ -170,7 +170,7 @@ InstallFunctions(MapIterator.prototype, DONT_ENUM, [
   'next', MapIteratorNextJS
 ]);
 
-%FunctionSetName(MapIteratorSymbolIterator, '[Symbol.iterator]');
+SetFunctionName(MapIteratorSymbolIterator, symbolIterator);
 %AddNamedProperty(MapIterator.prototype, symbolIterator,
     MapIteratorSymbolIterator, DONT_ENUM);
 %AddNamedProperty(MapIterator.prototype, symbolToStringTag,