Generate 45% faster query methods

`DEFAULT_VALUES` access is a bit slower, avoiding that makes about 45%
faster query methods.

https://gist.github.com/kamipo/e64439f7a206e1c5b5c69d92d982828e

Before (ff299f1):

```
Warming up --------------------------------------
        #limit_value   263.800k i/100ms
    #limit_value = 1   241.758k i/100ms
Calculating -------------------------------------
        #limit_value      7.044M (± 1.5%) i/s -     35.349M in   5.019511s
    #limit_value = 1      6.044M (± 2.3%) i/s -     30.220M in   5.003292s
```

After (this change):

```
Warming up --------------------------------------
        #limit_value   246.295k i/100ms
    #limit_value = 1   244.398k i/100ms
Calculating -------------------------------------
        #limit_value     10.303M (± 2.1%) i/s -     51.722M in   5.022568s
    #limit_value = 1      6.021M (± 6.1%) i/s -     30.061M in   5.015545s
```

Author: kamipo

activerecord/lib/active_record/relation/query_methods.rb

@@ -83,22 +83,25 @@ def not_behaves_as_nor?(opts)
     FROZEN_EMPTY_HASH = {}.freeze
 
     Relation::VALUE_METHODS.each do |name|
-      method_name = \
+      method_name, default =
         case name
-        when *Relation::MULTI_VALUE_METHODS then "#{name}_values"
-        when *Relation::SINGLE_VALUE_METHODS then "#{name}_value"
-        when *Relation::CLAUSE_METHODS then "#{name}_clause"
+        when *Relation::MULTI_VALUE_METHODS
+          ["#{name}_values", "FROZEN_EMPTY_ARRAY"]
+        when *Relation::SINGLE_VALUE_METHODS
+          ["#{name}_value", name == :create_with ? "FROZEN_EMPTY_HASH" : "nil"]
+        when *Relation::CLAUSE_METHODS
+          ["#{name}_clause", "DEFAULT_VALUES[:#{name}]"]
         end
+
       class_eval <<-CODE, __FILE__, __LINE__ + 1
-        def #{method_name}                   # def includes_values
-          default = DEFAULT_VALUES[:#{name}] #   default = DEFAULT_VALUES[:includes]
-          @values.fetch(:#{name}, default)   #   @values.fetch(:includes, default)
-        end                                  # end
-
-        def #{method_name}=(value)           # def includes_values=(value)
-          assert_mutability!                 #   assert_mutability!
-          @values[:#{name}] = value          #   @values[:includes] = value
-        end                                  # end
+        def #{method_name}                     # def includes_values
+          @values.fetch(:#{name}, #{default})  #   @values.fetch(:includes, FROZEN_EMPTY_ARRAY)
+        end                                    # end
+
+        def #{method_name}=(value)             # def includes_values=(value)
+          assert_mutability!                   #   assert_mutability!
+          @values[:#{name}] = value            #   @values[:includes] = value
+        end                                    # end
       CODE
     end