perf intel-pt: Add support for synthesizing branch stacks for regular events

perf intel-pt: Add support for synthesizing branch stacks for regular events

Use the new thread_stack__br_sample_late() function to create a thread
stack for regular events.

Example:

 # perf record --kcore --aux-sample -e '{intel_pt//,cycles:ppp}' -c 10000 uname
 Linux
 [ perf record: Woken up 2 times to write data ]
 [ perf record: Captured and wrote 0.743 MB perf.data ]
 # perf report --itrace=Le --stdio | head -30 | tail -18

 # Samples: 11K of event 'cycles:ppp'
 # Event count (approx.): 11648
 #
 # Overhead  Command  Source Shared Object  Source Symbol                 Target Symbol                 Basic Block Cycles
 # ........  .......  ....................  ............................  ............................  ..................
 #
      5.49%  uname    libc-2.30.so          [.] _dl_addr                  [.] _dl_addr                  -
      2.41%  uname    ld-2.30.so            [.] _dl_relocate_object       [.] _dl_relocate_object       -
      2.31%  uname    ld-2.30.so            [.] do_lookup_x               [.] do_lookup_x               -
      2.17%  uname    [kernel.kallsyms]     [k] unmap_page_range          [k] unmap_page_range          -
      2.05%  uname    ld-2.30.so            [k] _dl_start                 [k] _dl_start                 -
      1.97%  uname    ld-2.30.so            [.] _dl_lookup_symbol_x       [.] _dl_lookup_symbol_x       -
      1.94%  uname    [kernel.kallsyms]     [k] filemap_map_pages         [k] filemap_map_pages         -
      1.60%  uname    [kernel.kallsyms]     [k] __handle_mm_fault         [k] __handle_mm_fault         -
      1.44%  uname    [kernel.kallsyms]     [k] page_add_file_rmap        [k] page_add_file_rmap        -
      1.12%  uname    [kernel.kallsyms]     [k] vma_interval_tree_insert  [k] vma_interval_tree_insert  -
      0.94%  uname    [kernel.kallsyms]     [k] perf_iterate_ctx          [k] perf_iterate_ctx          -

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20200429150751.12570-8-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>