Handle default boolean column values when deduplicating

[aidanharan]

Fixed the "bit" type column error NoMethodError: undefined method '-@' for true:TrueClass.

Issue was that the default value for a column in the SQL Server adapter can be true/false. However, the true/false classes do not implement the '-@' method to return a frozen version of the value. However, since true/false are already frozen there is no need to call the -@ method anyway.

irb(main):0> 'test'.frozen?
=> false

irb(main):0> (-'test').frozen?
=> true

irb(main):0> -false
NoMethodError (undefined method `-@' for false:FalseClass)

irb(main):0> -true
NoMethodError (undefined method `-@' for true:TrueClass)

irb(main):0> false.frozen?
=> true

irb(main):0> true.frozen?
=> true

Tests Before
https://github.com/rails-sqlserver/activerecord-sqlserver-adapter/runs/2342106156
7133 runs, 8923 assertions, 36 failures, 3373 errors, 33 skips

Tests After
https://github.com/rails-sqlserver/activerecord-sqlserver-adapter/pull/875/checks?check_run_id=2342446944
7133 runs, 14121 assertions, 38 failures, 1590 errors, 37 skips