ci:check llgo test's stderr to exit

[luoliwoshang]

can exit expect when llgo test

https://github.com/goplus/llcppg/actions/runs/15177637874/job/42680771642?pr=364
https://github.com/goplus/llcppg/actions/runs/15177637874/job/42680866353?pr=364

Run # llgo test ./_xtool/internal/parser/...
todo: unknown builtin type: Ibm128
--- FAIL: TestBuiltinType (0.02s)
    ???:1: Void Kind mismatch:got 0 want 1, 
FAIL
/home/runner/go/bin/parser.test: exit code 1
llgo test fail
Error: Process completed with exit code 1.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.43%. Comparing base (6194a92) to head (a071b69).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #364   +/-   ##
=======================================
  Coverage   80.43%   80.43%           
=======================================
  Files          28       28           
  Lines        3496     3496           
=======================================
  Hits         2812     2812           
  Misses        645      645           
  Partials       39       39           

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