Fix performance degradation introduced in c2547ab

After discussing with someone, our current running theory is that the local
variable forces the compiler to reserve an additional register for the whole
lifespan of the function. Dropping it and just loading the value should restore
the previous code generation.

Closes GH-9876

Zend/zend_hash.c

@@ -658,15 +658,14 @@ ZEND_API void ZEND_FASTCALL zend_hash_iterators_advance(HashTable *ht, HashPosit
 /* Hash must be known and precomputed before */
 static zend_always_inline Bucket *zend_hash_find_bucket(const HashTable *ht, const zend_string *key)
 {
-	zend_ulong key_hash = ZSTR_H(key);
 	uint32_t nIndex;
 	uint32_t idx;
 	Bucket *p, *arData;
 
-	ZEND_ASSERT(key_hash != 0 && "Hash must be known");
+	ZEND_ASSERT(ZSTR_H(key) != 0 && "Hash must be known");
 
 	arData = ht->arData;
-	nIndex = key_hash | ht->nTableMask;
+	nIndex = ZSTR_H(key) | ht->nTableMask;
 	idx = HT_HASH_EX(arData, nIndex);
 
 	if (UNEXPECTED(idx == HT_INVALID_IDX)) {
@@ -678,7 +677,7 @@ static zend_always_inline Bucket *zend_hash_find_bucket(const HashTable *ht, con
 	}
 
 	while (1) {
-		if (p->h == key_hash &&
+		if (p->h == ZSTR_H(key) &&
 		    EXPECTED(p->key) &&
 		    zend_string_equal_content(p->key, key)) {
 			return p;