Remove deprecated assert method

Author: mac-cain13

Diff for: Library/Core/Validatable.swift

@@ -27,23 +27,3 @@ public protocol Validatable {
    */
   static func validate() throws
 }
-
-extension Validatable {
-  /**
-   Validates this entity and asserts if it encounters a invalid situation, a validatable should also validate it sub-validatables if it has any. In -O builds (the default for Xcode's Release configuration), validation is not evaluated, and there are no effects.
-   */
-  @available(*, deprecated, message: "Use validate() instead, preferably from a testcase.")
-  public static func assertValid() {
-    assert( theRealAssert() )
-  }
-
-  fileprivate static func theRealAssert() -> Bool {
-    do {
-      try validate()
-    } catch {
-      assertionFailure("Validation of \(type(of: self)) failed with error: \(error)")
-    }
-
-    return true
-  }
-}