Fix `TimeWithZone#eql?` to handle `TimeWithZone` created from `DateTime`

Before:

```ruby
  twz = DateTime.now.in_time_zone
  twz.eql?(twz.dup) => false
```

Now:

```ruby
  twz = DateTime.now.in_time_zone
  twz.eql?(twz.dup) => true
```

Please notice that this fix the `TimeWithZone` comparison to itself,
not to `DateTime`. Based on #3725, `DateTime` should not be equal to
`TimeWithZone`.

1 files changed, 1 insertions, 1 deletions

diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
index 412c72d27c..f8f1b9ac2c 100644
--- a/activesupport/lib/active_support/time_with_zone.rb
+++ b/activesupport/lib/active_support/time_with_zone.rb
@@ -247,7 +247,7 @@ module ActiveSupport
     end
 
     def eql?(other)
-      utc.eql?(other)
+      other.eql?(utc)
     end
 
     def hash