Rename/merge test files.

...ary/Homebrew/test/helper/integration_command_test_case.rb

Library/Homebrew/test/test_ENV.rb

Library/Homebrew/test/test_analytics.rb

Library/Homebrew/test/test_audit.rb

Library/Homebrew/test/test_bottle.rb

Library/Homebrew/test/test_bundle.rb

Library/Homebrew/test/test_cache.rb

Library/Homebrew/test/test_cache_formula.rb

Library/Homebrew/test/test_cask.rb

Library/Homebrew/test/test_cat.rb

Library/Homebrew/test/test_cellar.rb

Library/Homebrew/test/test_cellar_formula.rb

Library/Homebrew/test/test_cleanup.rb

Library/Homebrew/test/test_command.rb

Library/Homebrew/test/test_commands.rb

Library/Homebrew/test/test_config.rb

Library/Homebrew/test/test_create.rb

Library/Homebrew/test/test_custom_command.rb

Library/Homebrew/test/test_deps.rb

Library/Homebrew/test/test_desc.rb