perf tracepoint: Sort events in iterator

perf tracepoint: Sort events in iterator

In print_tracepoint_events() use tracing_events__scandir_alphasort() and
scandir alphasort so that the subsystem and events are sorted and don't
need a secondary qsort. Locally this results in the following change:

...
   ext4:ext4_zero_range                               [Tracepoint event]
-  fib6:fib6_table_lookup                             [Tracepoint event]
   fib:fib_table_lookup                               [Tracepoint event]
+  fib6:fib6_table_lookup                             [Tracepoint event]
   filelock:break_lease_block                         [Tracepoint event]
...

ie fib6 now is after fib and not before it. This is more consistent
with how numbers are more generally sorted, such as:

...
  syscalls:sys_enter_renameat                        [Tracepoint event]
  syscalls:sys_enter_renameat2                       [Tracepoint event]
...

and so an improvement over the qsort approach.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Weilin Wang <weilin.wang@intel.com>
Cc: Xin Gao <gaoxin@cdjrlc.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: http://lore.kernel.org/lkml/20221114210723.2749751-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>