Support magical constants

[zonuexe]

Before

After

[zonuexe]

To improve the visibility of test results:

Before

Test php-mode-test-constants condition:
    (ert-test-failed
     ((should
       (eq 'php-constant
	    (get-text-property ... ...)))
      :form
      (eq php-constant php-magical-constant)
      :value nil))

After

Test php-mode-test-constants condition:
    (ert-test-failed
     ((should
       (equal
	(cons variable ...)
	(cons variable ...)))
      :form
      (equal
       ("class;" . php-constant)
       ("class;" . php-magical-constant))
      :value nil :explanation
      (cdr
       (different-atoms php-constant php-magical-constant))))

[zonuexe]

NOTE: __COMPILER_HALT_OFFSET__ is similar to a magical constant, but it is not. It is possible to add it to the list but I am lost.

<?php

echo __COMPILER_HALT_OFFSET__, PHP_EOL;
echo \__COMPILER_HALT_OFFSET__, PHP_EOL;

__halt_compiler();

https://3v4l.org/Ot9M0