Ensure only one Promise constructor is ever used by tools code.

tools/cli/dev-bundle-bin-commands.js

@@ -1,8 +1,6 @@
 // Note that this file is required before we install our Babel hooks in
 // ../tool-env/install-babel.js, so we can't use ES2015+ syntax here.
 
-var Promise = global.Promise || require("promise/lib/es6-extensions");
-
 var win32Extensions = {
   node: ".exe",
   npm: ".cmd"

tools/cli/dev-bundle.js

@@ -8,7 +8,6 @@
 var fs = require("fs");
 var path = require("path");
 var rootDir = path.resolve(__dirname, "..", "..");
-var Promise = global.Promise || require("promise/lib/es6-extensions");
 var defaultDevBundlePromise =
   Promise.resolve(path.join(rootDir, "dev_bundle"));
 

tools/index.js

@@ -1,3 +1,9 @@
+// Install a global ES2015-compliant Promise constructor that knows how to
+// run all its callbacks in Fibers.
+var Promise = global.Promise = global.Promise ||
+  require("promise/lib/es6-extensions");
+require("meteor-promise").makeCompatible(Promise, require("fibers"));
+
 require("./cli/dev-bundle-bin-commands.js").then(function (child) {
   if (! child) {
     // Use process.nextTick here to prevent the Promise from swallowing

tools/tool-env/install-runtime.js

@@ -2,12 +2,6 @@
 // Symbol, Map, and Set, patching the native implementations if available.
 require("meteor-ecmascript-runtime");
 
-// Install a global ES2015-compliant Promise constructor that knows how to
-// run all its callbacks in Fibers.
-var Promise = global.Promise = global.Promise ||
-  require("promise/lib/es6-extensions");
-require("meteor-promise").makeCompatible(Promise, require("fibers"));
-
 // Verify that the babel-runtime package is available to be required.
 // The .join("/") prevents babel-plugin-transform-runtime from
 // "intelligently" converting this to an import statement.