Restore error message incorrectly removed by commit 10d43c4 (related to GH-15497)

Author: dstogov

ext/opcache/zend_shared_alloc.c

@@ -366,6 +366,11 @@ void *zend_shared_alloc(size_t size)
 		zend_accel_error_noreturn(ACCEL_LOG_ERROR, "Possible integer overflow in shared memory allocation (%zu + %zu)", size, PLATFORM_ALIGNMENT);
 	}
 
+#if 1
+	if (!ZCG(locked)) {
+		zend_accel_error_noreturn(ACCEL_LOG_ERROR, "Shared memory lock not obtained");
+	}
+#endif
 	if (block_size > ZSMMG(shared_free)) { /* No hope to find a big-enough block */
 		SHARED_ALLOC_FAILED();
 		return NULL;