Fix use-after-free in extract() EXTR_REFS collision modes#22696
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The phpGH-18209 fix guarded only php_extract_ref_overwrite. The other five per-collision-mode helpers (if_exists, prefix_if_exists, prefix_same, prefix_all, prefix_invalid), split out when extract() was refactored, kept the pre-fix order: they dropped the old value of orig_var before writing the new reference. A destructor run by that drop can unset the symbol being written, so the following ZVAL_REF wrote into freed memory. Apply the same swap-then-dtor already used by php_extract_ref_overwrite: copy the old value aside, write the reference, then drop the copy. Fixes phpGH-18209
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The GH-18209 fix guarded
php_extract_ref_overwriteagainst a destructor freeing the extract target during the reference write, but the five sibling EXTR_REFS collision paths still drop the old value before writing the reference. The added test crashes on master through the EXTR_IF_EXISTS and EXTR_PREFIX_ALL paths; the fix copies the old value aside and drops it after the write, matchingphp_extract_ref_overwrite.Fixes GH-18209