EC2: Include LLDB in small and builder AMIs

I excluded lldb from the "small" and "builder" flavours of EC2 AMIs
because on FreeBSD 14.x the lldb binary was 100 MB, as a result of
statically linking in lots of LLVM code; but we now have libprivatellvm
as a shared library and lldb is much smaller so there's no significant
benefit to excluding it.

Reviewed by: ivy
MFC after: 3 days
Sponsored by: https://www.patreon.com/cperciva
Differential Revision: https://reviews.freebsd.org/D52921