Unit Tests: PHPCS checks

[dd32]

A number of checks included in PHPCS are not currently unit tested.

• [ ] WordPress.DB.PreparedSQL
• [ ] WordPress.DB.PreparedSQL.InterpolatedNotPrepared
• [ ] WordPress.DB.PreparedSQLPlaceholders
• [ ] WordPress.Security.NonceVerification
• [x] Generic.PHP.BacktickOperator
• [x] Generic.PHP.DiscourageGoto.Found
• [x] Generic.PHP.DisallowShortOpenTag
• [x] Generic.PHP.DisallowAlternativePHPTags
• [ ] WordPress.Security.PluginMenuSlug
• [ ] WordPress.DB.RestrictedClasses
• [ ] WordPress.DB.RestrictedFunctions
• [ ] WordPress.WP.AlternativeFunction
• [x] Generic.PHP.ForbiddenFunctions
• [ ] WordPress.WP.DeprecatedClasses
• [ ] WordPress.WP.DeprecatedFunctions
• [ ] WordPress.WP.DeprecatedParameters
• [ ] WordPress.DateTime.RestrictedFunctions
• [ ] WordPress.WP.DiscouragedConstants
• [ ] WordPress.WP.DeprecatedParameterValues