fix(e2e): 234 must pin a toolchain per platform, not only default

macOS 上直接死在第一步:

    [xlings] 'xim:gcc@16.1.0' not in current index

而测试把它报成「build with bmi_schedule=on failed」—— 完全是另一个诊断。
补上和目录里其他 e2e 一样的三行(macos = llvm@22.1.8 / windows = llvm@20.1.7)。

在 clang 上策略是 two-phase、没有信号量,测试本来就会跳过第 3、4 节并说明原因,
所以这三行让它在三个平台上各测各该测的,而不是只在 Linux 上有意义。

Author: speak-agent

tests/e2e/234_bmi_schedule_on.sh

@@ -46,13 +46,21 @@ TMP=$(mktemp -d)
 trap "rm -rf $TMP" EXIT
 cd "$TMP"
 
+# ⚠️ PIN PER PLATFORM, not just `default`. A bare `default = "gcc@16.1.0"` sends
+# macOS and Windows looking for a gcc payload that does not exist for them, and
+# the whole test dies at step 1 with `'xim:gcc@16.1.0' not in current index` —
+# reported as "the build with bmi_schedule=on failed", which is a completely
+# different diagnosis. Same three-line block every other e2e in this directory
+# uses.
 cat > mcpp.toml <<'EOF'
 [package]
 name    = "schedon"
 version = "0.1.0"
 
 [toolchain]
 default = "gcc@16.1.0"
+macos   = "llvm@22.1.8"
+windows = "llvm@20.1.7"
 
 [build]
 bmi_schedule = "on"