Move Cask fixtures to `test/support/fixtures`.

Library/Homebrew/cask/lib/hbc.rb

Library/Homebrew/cask/spec/cask/artifact/binary_spec.rb

Library/Homebrew/cask/spec/spec_helper.rb

Library/Homebrew/cask/test/cask/accessibility_test.rb

Library/Homebrew/cask/test/cask/artifact/alt_target_test.rb

Library/Homebrew/cask/test/cask/artifact/app_test.rb

...Homebrew/cask/test/cask/artifact/generic_artifact_test.rb

...Homebrew/cask/test/cask/artifact/nested_container_test.rb

Library/Homebrew/cask/test/cask/artifact/pkg_test.rb

Library/Homebrew/cask/test/cask/artifact/suite_test.rb

...Homebrew/cask/test/cask/artifact/two_apps_correct_test.rb

...mebrew/cask/test/cask/artifact/two_apps_incorrect_test.rb

Library/Homebrew/cask/test/cask/artifact/uninstall_test.rb

Library/Homebrew/cask/test/cask/artifact/zap_test.rb

Library/Homebrew/cask/test/cask/cli/fetch_test.rb

Library/Homebrew/cask/test/cask/cli/install_test.rb

Library/Homebrew/cask/test/cask/cli/list_test.rb

Library/Homebrew/cask/test/cask/cli/reinstall_test.rb

Library/Homebrew/cask/test/cask/cli/uninstall_test.rb

Library/Homebrew/cask/test/cask/cli/zap_test.rb