* 3.4:
  Add Tagalog translations for validator messages 94, 95, 96 and 99
  PHPUnit's assertContains() performs strict comparisons now.
  [ClassLoader][Routing] Fix namespace parsing on php 8.
  Fix deprecated libxml_disable_entity_loader
  Made reference to PHPUnit\Util\XML::loadfile php5-compatible.
  [Validator] Add missing translations for german and vietnamese
  Modernized deprecated PHPUnit assertion calls
  [Console] The message of "class not found" errors has changed in php 8.
  The PHPUnit\Util\XML class has been removed in PHPUnit 9.3.
  [Console] Make sure we pass a numeric array of arguments to call_user_func_array().
  [Serializer] Fix that it will never reach DOMNode
  [Validator] sync translations
  [VarDumper] Improve previous fix on light array coloration
  [Cache] Fix #37667

…block (jnye)

This PR was squashed before being merged into the 3.4 branch.

Discussion
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[Yaml] Fix for #36624; Allow PHP constant as first key in block

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix #36624
| License       | MIT
| Doc PR        |

When using a PHP constant in the first key of a mapping the parser would throw an exception. However if you used a PHP constant in any other key but the first it was allowed. This fix allows PHP constant as the first key.

I've included a test for this parser error along with the fix.

Commits
-------

46f635c492 [Yaml] Fix for #36624; Allow PHP constant as first key in block

* 3.4:
  [Yaml] Fix for #36624; Allow PHP constant as first key in block
  Use PHPUnit 9.3 on php 8.
  fix mapping errors from unmapped forms
  [Validator] Add target guards for Composite nested constraints

* 3.4:
  account for is_numeric() behavior changes in PHP 8
  fix expected exception messages on PHP 8

* 3.4:
  Backport: Improve link script with rollback when using symlink
  fix more numeric cases changing in PHP 8