perf jit: Move test functionality in to a test

perf jit: Move test functionality in to a test

Adds a test for minimal jit_write_elf functionality.

Committer testing:

  # perf test jit
  61: Test jit_write_elf                                    : Ok
  #

  # perf test -v jit
  61: Test jit_write_elf                                    :
  --- start ---
  test child forked, pid 10460
  Writing jit code to: /tmp/perf-test-KqxURR
  test child finished with 0
  ---- end ----
  Test jit_write_elf: Ok
  #

Committer notes:

Fix up the case where HAVE_JITDUMP is no defined.

Signed-off-by: Ian Rogers <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alexios Zavras <[email protected]>
Cc: Allison Randal <[email protected]>
Cc: Florian Fainelli <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kate Stewart <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Michael Petlan <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>