[scudo][standalone] Add missing va_end() in ScopedString::append

In ScopedString::append va_list ArgsCopy is created but never cleanuped
which can lead to undefined behaviour, like stack corruption.

Reviewed By: cryptoad

Differential Revision: https://reviews.llvm.org/D92383

GitOrigin-RevId: 0a09c1cc9dcbec8126344123e9481bed6524e5ec
1 file changed