Bypass sigchild detection if phpinfo is not available
bug #10285 Bypass sigchild detection if phpinfo is not available (Seldaek)

This PR was merged into the 2.3 branch.

Discussion
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Bypass sigchild detection if phpinfo is not available

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | composer/composer#2711
| License       | MIT
| Doc PR        | none

This fixes composer/composer#2711, i.e. anyone disabling phpinfo for security (by obscurity, but whatever) reasons can not use the Process class anymore.

Commits
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714aee9 Bypass sigchild detection if phpinfo is not available
Revert "bug #10207 [DomCrawler] Fixed filterXPath() chaining (robbertkl)"

This reverts commit c11c5888f31bd663dcdb12b5b3558e0897601a23, reversing
changes made to e453c4589d81a93d22a2d927a1f9282d3d72c994.
Merge branch '2.3' into 2.4

* 2.3:
  Revert "bug #10207 [DomCrawler] Fixed filterXPath() chaining (robbertkl)"
  Bypass sigchild detection if phpinfo is not available

Conflicts:
	src/Symfony/Component/DomCrawler/Crawler.php