Avoid redundant `time.getutc` call if it is already utc time object

Currently `type.serialize` and `connection.{quote|type_cast}` for a time
object always does `time.getutc` call regardless of whether it is
already utc time object or not, that duplicated proccess
(`connection.type_cast(type.serialize(time))`) allocates extra/useless
time objects for each type casting.

This avoids that redundant `time.getutc` call if it is already utc time
object. In the case of a model has timestamps (`created_at` and
`updated_at`), it avoids 6,000 time objects allocation for 1,000 times
`model.save`.

```ruby
ObjectSpace::AllocationTracer.setup(%i{path line type})

pp ObjectSpace::AllocationTracer.trace {
  1_000.times { User.create }
}.select { |k, _| k[0].end_with?("quoting.rb", "time_value.rb") }
```

Before (c104bfe424e6cebe9c8e85a38515327a6c88b1f8):

```
{["~/rails/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb",
  203,
  :T_ARRAY]=>[1004, 0, 778, 0, 1, 0],
 ["~/rails/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb",
  220,
  :T_STRING]=>[2, 0, 2, 1, 1, 0],
 ["~/rails/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb",
  209,
  :T_ARRAY]=>[8, 0, 8, 1, 1, 0],
 ["~/rails/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb",
  57,
  :T_ARRAY]=>[4, 0, 4, 1, 1, 0],
 ["~/rails/activemodel/lib/active_model/type/helpers/time_value.rb",
  17,
  :T_DATA]=>[4000, 0, 3096, 0, 1, 0],
 ["~/rails/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb",
  120,
  :T_DATA]=>[2000, 0, 1548, 0, 1, 0],
 ["~/rails/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb",
  126,
  :T_STRING]=>[4000, 0, 3096, 0, 1, 0]}
```

After (this change):

```
{["~/rails/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb",
  203,
  :T_ARRAY]=>[1004, 0, 823, 0, 1, 0],
 ["~/rails/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb",
  220,
  :T_STRING]=>[2, 0, 2, 1, 1, 0],
 ["~/rails/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb",
  209,
  :T_ARRAY]=>[8, 0, 8, 1, 1, 0],
 ["~/rails/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb",
  57,
  :T_ARRAY]=>[4, 0, 4, 1, 1, 0],
 ["~/rails/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb",
  126,
  :T_STRING]=>[2000, 0, 1638, 0, 1, 0]}
```

0 files changed, 0 insertions, 0 deletions