Remove all harmony runtime flags which shipped in M51

src/js/arraybuffer.js

Index: src/js/arraybuffer.js
diff --git a/src/js/arraybuffer.js b/src/js/arraybuffer.js
index e739960e5be8a21c063a546c960d8114c2f14967..b602dcbf259f8d6625f80f66a551c6db3891a4f2 100644
--- a/src/js/arraybuffer.js
+++ b/src/js/arraybuffer.js
@@ -16,6 +16,7 @@ var MakeTypeError;
 var MaxSimple;
 var MinSimple;
 var SpeciesConstructor;
+var speciesSymbol = utils.ImportNow("species_symbol");
 
 utils.Import(function(from) {
   MakeTypeError = from.MakeTypeError;
@@ -84,6 +85,13 @@ function ArrayBufferSlice(start, end) {
   return result;
 }
 
+
+function ArrayBufferSpecies() {
+  return this;
+}
+
+utils.InstallGetter(GlobalArrayBuffer, speciesSymbol, ArrayBufferSpecies);
+
 utils.InstallGetter(GlobalArrayBuffer.prototype, "byteLength",
                     ArrayBufferGetByteLen);