Recombine atomic rules in composit rules after the simplification to improve readability

[jclaveau]

Depending on the DB server, this could be used top optimize generated queries.

The code below:

$filter = (new LogicalFilter([
    'and',
    ['field_1', '=', 2],
    [
        'or',
        ['field_2', '>', 4],
        ['field_2', '<', -4],
    ]
]))
->simplify()
->dump()
;

Would dump:

array (
  0 => 'or',
  1 => 
  array (
    0 => 'and',
    1 => 
    array (
      0 => 'field_1',
      1 => '=',
      2 => 2,
    ),
    2 => 
    array (
      0 => 'field_2',
      1 => '>',
      2 => 4,
    ),
  ),
  2 => 
  array (
    0 => 'and',
    1 => 
    array (
      0 => 'field_1',
      1 => '=',
      2 => 2,
    ),
    2 => 
    array (
      0 => 'field_2',
      1 => '<',
      2 => -4,
    ),
  ),
)

= and < opertations could be merged in ">=" / "<=" operations (same for in)

[jclaveau]

duplicate of #66