dtrace: require assembler symbol stripping and debug info

dtrace: require assembler symbol stripping and debug info

The former is needed because dt_module.c doesn't know how to ignore assembler
labels when reading module symbol data: the latter because dwarf2ctf reads the
types out of debug info.

Use select rather than require because both of these requirements are distinctly
non-obvious and we don't want to force people to hunt about for them.

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>