perf annotate: Split branch stack cycles info from 'struct annotation'

The cycles info is only meaningful when sample has branch stacks.  To
save the memory for normal cases, move those fields to a new 'struct
annotated_branch' and dynamically allocate it when needed.  Also move
cycles_hist from annotated_source as it's related here.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20231103191907.54531-3-namhyung@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>