build: remove the unused source-map-test (angular#46518)

As source-map-test is unused and obsolete at this point, removing it from the repository.

PR Close angular#46518

Author: josephperrott

.pullapprove.yml

@@ -1132,7 +1132,6 @@ groups:
           'tools/rxjs/**',
           'tools/saucelabs/**',
           'tools/size-tracking/**',
-          'tools/source-map-test/**',
           'tools/symbol-extractor/**',
           'tools/testing/**',
           'tools/tslint/**',

gulpfile.js

@@ -18,5 +18,4 @@ function loadTask(fileName, taskName) {
 }
 
 
-gulp.task('source-map-test', loadTask('source-map-test'));
 gulp.task('changelog:zonejs', loadTask('changelog-zonejs'));