perf examples bpf: Remove augmented_syscalls.c, the raw_syscalls one should be used instead

The attempt at using BPF to copy syscall pointer arguments to show them
like strace does started with sys_{enter,exit}_SYSCALL_NAME tracepoints,
in tools/perf/examples/bpf/augmented_syscalls.c, but then achieving this
result using raw_syscalls:{enter,exit} and BPF tail calls was deemed
more flexible.

The 'perf trace' codebase was adapted to using it while trying to
continue supporting the old style per-syscall tracepoints, which at some
point became too unwieldly and now isn't working properly.

So lets scale back and concentrate on the augmented_raw_syscalls.c
model on the way to using BPF skeletons.

For the same reason remove the etcsnoop.c example, that used the
old style per-tp syscalls just for the 'open' and 'openat' syscalls,
looking at the pathnames starting with "/etc/", we should be able
to do this later using filters, after we move to BPF skels.

The augmented_raw_syscalls.c one continues to work, now with libbpf 1.0,
after Ian work on using the libbpf map style:

  # perf trace -e ~acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c,open* --max-events 4
     0.000 ping/194815 openat(dfd: CWD, filename: "/etc/hosts", flags: RDONLY|CLOEXEC) = 5
    20.225 systemd-oomd/972 openat(dfd: CWD, filename: "/proc/meminfo", flags: RDONLY|CLOEXEC) = 12
    20.285 abrt-dump-jour/1371 openat(dfd: CWD, filename: "/var/log/journal/d6a97235307247e09f13f326fb607e3c/system.journal", flags: RDONLY|CLOEXEC|NONBLOCK) = 21
    20.301 abrt-dump-jour/1370 openat(dfd: CWD, filename: "/var/log/journal/d6a97235307247e09f13f326fb607e3c/system.journal", flags: RDONLY|CLOEXEC|NONBLOCK) = 21
  #

This is using this:

  # cat ~/.perfconfig
  [trace]
	show_zeros = yes
	show_duration = no
	no_inherit = yes
	args_alignment = 40

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>