Remove all harmony runtime flags which shipped in M51

src/js/promise.js

Index: src/js/promise.js
diff --git a/src/js/promise.js b/src/js/promise.js
index 1295363d97f65fd6e14f7ca3fa86f9c79b61093e..5e8c460ddfcaedfc7582b846c90e0f54b7f53ac8 100644
--- a/src/js/promise.js
+++ b/src/js/promise.js
@@ -27,6 +27,7 @@ var promiseRawSymbol = utils.ImportNow("promise_raw_symbol");
 var promiseStateSymbol = utils.ImportNow("promise_state_symbol");
 var promiseResultSymbol = utils.ImportNow("promise_result_symbol");
 var SpeciesConstructor;
+var speciesSymbol = utils.ImportNow("species_symbol");
 var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol");
 
 utils.Import(function(from) {
@@ -563,6 +564,11 @@ function PromiseHasUserDefinedRejectHandler() {
   return PromiseHasUserDefinedRejectHandlerRecursive(this);
 };
 
+
+function PromiseSpecies() {
+  return this;
+}
+
 // -------------------------------------------------------------------
 // Install exported functions.
 
@@ -577,6 +583,8 @@ utils.InstallFunctions(GlobalPromise, DONT_ENUM, [
   "resolve", PromiseResolve
 ]);
 
+utils.InstallGetter(GlobalPromise, speciesSymbol, PromiseSpecies);
+
 utils.InstallFunctions(GlobalPromise.prototype, DONT_ENUM, [
   "then", PromiseThen,
   "catch", PromiseCatch