Add direct-write fast path for bare-name keys in MANGLED_VARS mode

When $vars is a flat dictionary of bare property names (no
"\0ClassName\0prop" mangling), the pre-existing MANGLED_VARS parser
resolved each key to (scope, name), stashed it in an intermediate
scoped_props HashTable, then ran the regular scoped-mode write in a
second pass. Pure overhead for the common case.

The parser now resolves the property_info for each bare key and, when
it points at a real backed declared property, writes via
dc_write_backed_property() immediately — skipping the scoped_props
accumulation and the second-pass iteration. NUL-prefix (mangled) keys,
unresolved names, and hooked/virtual properties keep the original path
so error handling, scope tracking, and per-scope EG(fake_scope) stay
unchanged.

Bench, Customer (11 fields, 3-level inheritance), 100-entity batch
on PHP 8.4:

| shape                                               | before | after |
|-----------------------------------------------------|-------:|------:|
| deepclone_hydrate($class, $flatRow, MANGLED_VARS)   |  1,275 |   486 |
| Doctrine setValue loop (reference, unchanged)       |  1,131 | 1,131 |

That's a 2.33x speedup over Doctrine's current approach, down to
within ~58 ns of the hand-built scoped-shape path. The Doctrine pitch
becomes "pass the PDO row dict as-is, done." — no per-row scope
grouping, no mangled-key construction.

Author: nicolas-grekas

deepclone.c

@@ -3101,6 +3101,25 @@ PHP_FUNCTION(deepclone_hydrate)
 				/* Bare name — find declaring class */
 				real_name = prop_key;
 				zend_property_info *pi = zend_hash_find_ptr(&obj_ce->properties_info, real_name);
+
+				/* Fast path: the resolved property has a real backing slot (typed or
+				 * non-hooked). Write directly via dc_write_backed_property and skip the
+				 * scoped_props accumulation + second-pass write. This is the hot case
+				 * for Doctrine-style `fetchAll()` flows where the row is a flat dict
+				 * of declared field names. */
+				if (pi && !(pi->flags & ZEND_ACC_STATIC) && dc_is_backed_declared_property(pi)) {
+					zval *v = prop_val;
+					if (!(flags & DEEPCLONE_HYDRATE_PRESERVE_REFS)) {
+						ZVAL_DEREF(v);
+					}
+					if (UNEXPECTED(!dc_write_backed_property(Z_OBJ(obj_zval), pi, real_name, v, flags))) {
+						if (scoped_owned) zval_ptr_dtor(&local_scoped);
+						zval_ptr_dtor(&obj_zval);
+						RETURN_THROWS();
+					}
+					continue;
+				}
+
 				if (pi && !(pi->flags & ZEND_ACC_STATIC)) {
 					scope_str = pi->ce->name;
 					/* For private-set properties, use the declaring class as write scope */