host: detect at least some unsupported syscalls if kallsyms is not available
host: detect at least some unsupported syscalls if kallsyms is not available

We know how to detect availability of at least some syscalls without kallsyms. Do it.

dotweiba/syzkaller,sploving/syzkaller,xairy/syzkaller,dotweiba/syzkaller,google/syzkaller,zoulasc/syzkaller,google/syzkaller,xairy/syzkaller,dotweiba/syzkaller,zoulasc/syzkaller,xairy/syzkaller,dotweiba/syzkaller,xairy/syzkaller,hyz0906/syzkaller,hyz0906/syzkaller,sploving/syzkaller,xairy/syzkaller,sploving/syzkaller,hyz0906/syzkaller,google/syzkaller,google/syzkaller,zoulasc/syzkaller,hyz0906/syzkaller,zoulasc/syzkaller,sploving/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,hyz0906/syzkaller,xairy/syzkaller