Short-circuit blank? on date and time values

The concept of a blank date or time doesn't make sense so we can short
circuit the calls for `blank?` on these classes to gain small speed boost.

Fixes rails#21657

activesupport/CHANGELOG.md

@@ -1,3 +1,9 @@
+*   Short-circuit `blank?` on date and time values since they are never blank.
+
+    Fixes #21657
+
+    *Andrew White*
+
 *   Replaced deprecated `ThreadSafe::Cache` with its successor `Concurrent::Map` now that
     the thread_safe gem has been merged into concurrent-ruby.
 

activesupport/lib/active_support/core_ext/date.rb

@@ -1,5 +1,5 @@
 require 'active_support/core_ext/date/acts_like'
+require 'active_support/core_ext/date/blank'
 require 'active_support/core_ext/date/calculations'
 require 'active_support/core_ext/date/conversions'
 require 'active_support/core_ext/date/zones'
-

activesupport/lib/active_support/core_ext/date/blank.rb

@@ -0,0 +1,12 @@
+require 'date'
+
+class Date #:nodoc:
+  # No Date is blank:
+  #
+  #   Date.today.blank? # => false
+  #
+  # @return [false]
+  def blank?
+    false
+  end
+end

activesupport/lib/active_support/core_ext/date_time.rb

@@ -1,4 +1,5 @@
 require 'active_support/core_ext/date_time/acts_like'
+require 'active_support/core_ext/date_time/blank'
 require 'active_support/core_ext/date_time/calculations'
 require 'active_support/core_ext/date_time/conversions'
 require 'active_support/core_ext/date_time/zones'

activesupport/lib/active_support/core_ext/date_time/blank.rb

@@ -0,0 +1,12 @@
+require 'date'
+
+class DateTime #:nodoc:
+  # No DateTime is ever blank:
+  #
+  #   DateTime.now.blank? # => false
+  #
+  # @return [false]
+  def blank?
+    false
+  end
+end

activesupport/lib/active_support/core_ext/object/blank.rb

@@ -127,3 +127,14 @@ def blank?
     false
   end
 end
+
+class Time #:nodoc:
+  # No Time is blank:
+  #
+  #   Time.now.blank? # => false
+  #
+  # @return [false]
+  def blank?
+    false
+  end
+end

activesupport/lib/active_support/time_with_zone.rb

@@ -388,6 +388,11 @@ def is_a?(klass)
     end
     alias_method :kind_of?, :is_a?
 
+    # An instance of ActiveSupport::TimeWithZone is never blank
+    def blank?
+      false
+    end
+
     def freeze
       period; utc; time # preload instance variables before freezing
       super