perf annotate: Use libsubcmd's run-command.h to fork objdump

Reduce duplicated logic by using the subcmd library. Ensure when errors
occur they are reported to the caller. Before this patch, if no lines
are read the error status is 0.

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: clang-built-linux@googlegroups.com
Link: http://lore.kernel.org/lkml/20191010183649.23768-3-irogers@google.com
Link: http://lore.kernel.org/lkml/20191015003418.62563-1-irogers@google.com


[ merged follow up fix for NULL termination as in the 2nd link above ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>