[Debug] throw even in stacking mode to preserve code paths
bug #10989 [Debug] throw even in stacking mode to preserve code paths (nicolas-grekas)

This PR was merged into the 2.5 branch.

Discussion
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[Debug] throw even in stacking mode to preserve code paths

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no if throwing a parent class is accepted
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | none
| License       | MIT
| Doc PR        | none

Throwing \ErrorException instead of ContextErrorException is a better work around for https://bugs.php.net/42098

Commits
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d06b206 [Debug] throw even in stacking mode to preserve code paths