Eliminate race condition in web-library-build, since api-extractor now cannot run until after tsc has completed

Author: pgonzal

core-build/web-library-build/src/index.ts

@@ -52,8 +52,8 @@ tslint.mergeConfig({
 });
 
 // Define default task groups.
-export const compileTsTasks: IExecutable = parallel(typescript, text, apiExtractor);
-export const buildTasks: IExecutable = task('build', serial(preCopy, sass, parallel(tslint, compileTsTasks), postCopy));
+export const compileTsTasks: IExecutable = parallel(typescript, text);
+export const buildTasks: IExecutable = task('build', serial(preCopy, sass, parallel(tslint, compileTsTasks), apiExtractor, postCopy));
 export const bundleTasks: IExecutable = task('bundle', serial(buildTasks, webpack));
 export const testTasks: IExecutable = task('test', serial(buildTasks, karma, jest));
 export const defaultTasks: IExecutable = serial(bundleTasks, karma, jest);