Make Drupal core control the test suite(s)

In light of #2254825-8: Add coding standards tests for YAML definition files →

Background

1. There are ~4 test-bot/infrastructure maintainers.
2. There are 1,000+ core contributors.

Goal

1. Make Drupal core control the full test suite.
2. Enable alternative test categories/suites.
3. Make the "testbot" code accessible and move maintenance into Drupal core.

Proposed solution

1. $ core/scripts/test.sh
   
   Usage: core/scripts/test.sh <suite> [options] <path>
   
   Execute from the root directory of your Drupal site.
   
   Test suites:
   
     -a | --all            All available test suites.
          --phplint        PHP lint.
          --jslint         JS lint.
          --phpunit        PHPUnit.
          --simpletest     Simpletest.
   
   Arguments:
   
     <path>                The path for which to run tests.
   
   Argument examples:
   
     core                  Runs tests for all of core.
     core/modules/node     Runs tests for Node module.
     modules/devel         Runs tests for Devel module.
                           (assuming Devel module is located in /modules/devel)
   
   Options:
   
     -h | --help           This help.
     -v | --verbose        Enable verbose output.
     -o | --out <path>     Path to use for test results/artifacts.
                           Defaults to './test'.
          --color          Enable colorful output.
   
   Arguments and options can be specified in any order, as long as values for
   options that require a value are passed after the corresponding option.
   

Notes

1. This is explicitly limited to GNU Bash shells.

   Windows users (like me!) have to install Cygwin/Mingw32 to execute this script. Windows will not be supported natively.

   MacOSX and FreeBSD users have to install the GNU getopt port via sudo port install getopt. (details) Only Linux will be supported natively.