perf(): speed up www dev build

Author: manucorporat

src/compiler/config/test/validate-output-www.spec.ts

@@ -51,8 +51,8 @@ describe('validateOutputTargetWww', () => {
       'esmDir': path.join(rootDir, 'www', 'docs', 'build'),
       'isBrowserBuild': true,
       'polyfills': true,
-      'systemDir': path.join(rootDir, 'www', 'docs', 'build'),
-      'systemLoaderFile': path.join(rootDir, '/www/docs/build/undefined.js'),
+      'systemDir': undefined,
+      'systemLoaderFile': undefined,
       'type': 'dist-lazy'
     }, {
       'copyAssets': 'dist',

src/compiler/config/validate-outputs-www.ts

@@ -73,9 +73,9 @@ function validateOutputTarget(config: d.Config, diagnostics: d.Diagnostic[], out
   config.outputTargets.push({
     type: DIST_LAZY,
     esmDir: buildDir,
-    systemDir: buildDir,
+    systemDir: config.buildEs5 ? buildDir : undefined,
+    systemLoaderFile: config.buildEs5 ? config.sys.path.join(buildDir, `${config.fsNamespace}.js`) : undefined,
     polyfills: outputTarget.polyfills,
-    systemLoaderFile: config.sys.path.join(buildDir, `${config.fsNamespace}.js`),
     isBrowserBuild: true,
   });