Make sure Backdrop runs tests for install profiles and themes

[klonos]

This was discovered while working on #1285

@quicksketch

Backdrop didn't actually run tests provided by install profiles (or themes). I fixed that as well.

Well that was a bad idea. Other tests broke when I did that. So for now I've moved the testing of the Standard Profile into SimpleTest module, where we have a bunch of other system-wide tests.

[quicksketch]

In simpletest_test_get_all() we have the following:

      $files = backdrop_system_listing('/^' . BACKDROP_PHP_FUNCTION_PATTERN . '\.tests\.info$/', 'modules', 'name', 0);

This finds all *.tests.info files within all modules directories. But it doesn't include those in install profiles or themes. I tried "fixing" it by adding the following:

      $files = backdrop_system_listing('/^' . BACKDROP_PHP_FUNCTION_PATTERN . '\.tests\.info$/', 'modules', 'name', 0);
      $files = backdrop_system_listing('/^' . BACKDROP_PHP_FUNCTION_PATTERN . '\.tests\.info$/', 'themes', 'name', 0);
      $files = backdrop_system_listing('/^' . BACKDROP_PHP_FUNCTION_PATTERN . '\.tests\.info$/', 'profiles', 'name', 0);

But this resulted in a regression. Apparently modules within install profiles are intentionally excluded from running tests. By scanning the "profiles" directories, this would allow profile-specific modules to be tested.

This relates to a (still-open) Drupal.org issue at https://www.drupal.org/node/911354