Avoid redundant `attribute_alias?` before `attribute_alias`

If we want to get alias resolved attribute finally, we can use
`attribute_alias` directly.

For that purpose, avoiding redundant `attribute_alias?` makes alias
attribute access 40% faster.

https://gist.github.com/kamipo/e427f080a27b46f50bc508fae3612a0e

Before (2c0729d8):

```
Warming up --------------------------------------
          user['id']   102.668k i/100ms
      user['new_id']    80.660k i/100ms
        user['name']    99.368k i/100ms
    user['new_name']    81.626k i/100ms
Calculating -------------------------------------
          user['id']      1.431M (± 4.0%) i/s -      7.187M in   5.031985s
      user['new_id']      1.042M (± 4.2%) i/s -      5.243M in   5.039858s
        user['name']      1.406M (± 5.6%) i/s -      7.055M in   5.036743s
    user['new_name']      1.074M (± 3.6%) i/s -      5.387M in   5.024152s
```

After (this change):

```
Warming up --------------------------------------
          user['id']   109.775k i/100ms
      user['new_id']   103.303k i/100ms
        user['name']   105.988k i/100ms
    user['new_name']    99.618k i/100ms
Calculating -------------------------------------
          user['id']      1.520M (± 6.7%) i/s -      7.574M in   5.011496s
      user['new_id']      1.485M (± 6.2%) i/s -      7.438M in   5.036252s
        user['name']      1.538M (± 5.4%) i/s -      7.737M in   5.049765s
    user['new_name']      1.516M (± 4.6%) i/s -      7.571M in   5.007293s
```

3 files changed, 4 insertions, 12 deletions

diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
index 444568562b..a43ebdf60d 100644
--- a/activerecord/lib/active_record/attribute_methods/dirty.rb
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -167,12 +167,8 @@ module ActiveRecord
         end
 
         def write_attribute_without_type_cast(attr_name, value)
-          name = attr_name.to_s
-          if self.class.attribute_alias?(name)
-            name = self.class.attribute_alias(name)
-          end
-          result = super(name, value)
-          clear_attribute_change(name)
+          result = super
+          clear_attribute_change(attr_name)
           result
         end
 
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
index c787fb6a94..0562327a9a 100644
--- a/activerecord/lib/active_record/attribute_methods/read.rb
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -27,9 +27,7 @@ module ActiveRecord
       # to a date object, like Date.new(2004, 12, 12)).
       def read_attribute(attr_name, &block)
         name = attr_name.to_s
-        if self.class.attribute_alias?(name)
-          name = self.class.attribute_alias(name)
-        end
+        name = self.class.attribute_aliases[name] || name
 
         name = @primary_key if name == "id" && @primary_key
         _read_attribute(name, &block)
diff --git a/activerecord/lib/active_record/attribute_methods/write.rb b/activerecord/lib/active_record/attribute_methods/write.rb
index 6a54bd2fc2..1c63b553d0 100644
--- a/activerecord/lib/active_record/attribute_methods/write.rb
+++ b/activerecord/lib/active_record/attribute_methods/write.rb
@@ -31,9 +31,7 @@ module ActiveRecord
       # turned into +nil+.
       def write_attribute(attr_name, value)
         name = attr_name.to_s
-        if self.class.attribute_alias?(name)
-          name = self.class.attribute_alias(name)
-        end
+        name = self.class.attribute_aliases[name] || name
 
         name = @primary_key if name == "id" && @primary_key
         _write_attribute(name, value)