[libc] Remove sysconf from Scudo integration test entrypoints (#197639)
sysconf moved behind LLVM_LIBC_ENABLE_EXPERIMENTAL_ENTRYPOINTS in commit
8146920541c4. When that flag is OFF (the default), the target is not
built as an OBJECT library, so referencing it via add_entrypoint_library
causes a CMake generation error on the libc-x86_64-debian-fullbuild bot.
Scudo does not use sysconf, so this is a safe removal.
Assisted-by: Automated tooling, human reviewed.