When assigning a hash to a time attribute that's missing a year
component (e.g. a `time_select` with `:ignore_date` set to `true`)
then the year defaults to 1970 instead of the expected 2000. This
results in the attribute changing as a result of the save.

Before:

    event = Event.new(start_time: { 4 => 20, 5 => 30 })
    event.start_time # => 1970-01-01 20:30:00 UTC
    event.save
    event.reload
    event.start_time # => 2000-01-01 20:30:00 UTC

After:

    event = Event.new(start_time: { 4 => 20, 5 => 30 })
    event.start_time # => 2000-01-01 20:30:00 UTC
    event.save
    event.reload
    event.start_time # => 2000-01-01 20:30:00 UTC

Before it was coercing an invalid string into "2000-01-01 00:00:00".

For legacy reasons Rails stores time columns on sqlite as full
timestamp strings. However because the date component wasn't being
normalized this meant that when they were read back they were being
prefixed with 2001-01-01 by ActiveModel::Type::Time. This had a
twofold result - first it meant that the fast code path wasn't being
used because the string was invalid and second it was corrupting the
second fractional component being read by the Date._parse code path.

Fix this by a combination of normalizing the timestamps on writing
and also changing Active Model to be more lenient when detecting
whether a string starts with a date component before creating the
dummy time value for parsing.

In #20317, datetime columns had their precision applied on assignment but
that behaviour wasn't applied to time columns - this commit fixes that.

Fixes #30301.

This reverts commit 3420a145, reversing
changes made to afb66a5a.

The current code base is not uniform. After some discussion,
we have chosen to go with double quotes by default.

The first step of bringing typecasting to ActiveModel

The type code is actually quite accessible, and I'm planning to
encourage people to look at the files in the `type` folder to learn more
about how it works. This will help reduce the noise from code that is
less about type casting, and more about random AR nonsense.

This allows us to remove `Type::Value#klass`, as it was only used for
multi-parameter assignment to reach into the types internals. The
relevant type objects now accept a hash in addition to their previous
accepted arguments to `type_cast_from_user`. This required minor
modifications to the tests, since previously they were relying on the
fact that mulit-parameter assignement was reaching into the internals of
time zone aware attributes. In reaility, changing those properties at
runtime wouldn't change the accessor methods for all other forms of
assignment.

The types that are affected by `time_zone_aware_attributes` (which is on
by default) have been made configurable, in case this is a breaking
change for existing applications.

`ActiveRecord::ConnectionAdapters::Type::Value` =>
`ActiveRecord::Type::Value`