M2 spine: add `ext/standard/VmSplAutoload.php` to compiler_lib_spine_smoke

[PurHur]

Summary

Add ext/standard/VmSplAutoload.php to the M2 self-host spine bundle (test/selfhost/compiler_lib_spine_smoke/main.php) toward full bin/vm.php inventory closure.

Trackers

• Parent: 🔄 North Star 2: Compiler fully compiles itself (living tracker) #1056 (North Star 2 / M2)
• Wave: M2 wave 2: Grow compiler_lib_spine_smoke toward full vm.php inventory #1497
• Batch umbrella: M2 spine growth: batch tracker (compiler_lib_spine_smoke → full inventory) #1419

File

• ext/standard/VmSplAutoload.php

Gates

script/apply-patches.sh
php bin/compile.php -l test/selfhost/compiler_lib_spine_smoke/main.php
BOOTSTRAP_LIB_SPINE_SMOKE=1 make bootstrap-selfhost-lib-spine-smoke

How to close

1. Add require_once __DIR__.'/../../../ext/standard/VmSplAutoload.php'; (adjust depth) to test/selfhost/compiler_lib_spine_smoke/main.php
2. If ext/standard/Jit* or builtin leaf: confirm SelfHostBuiltinPolicy
3. php script/bootstrap-selfhost-next-includes.php --bundle=test/selfhost/compiler_lib_spine_smoke/main.php
4. Update spine count in docs/pages/development-status.md / docs/self-host-target.md

Label: m2-spine-unit