perf tests: Add breakpoint accounting/modify test

perf tests: Add breakpoint accounting/modify test

Adding test that:

  - detects the number of watch/break-points,
    skip test if any is missing
  - detects PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl,
    skip test if it's missing
  - detects if watchpoints and breakpoints share
    same slots
  - create all possible watchpoints on cpu 0
  - change one of it to breakpoint
  - in case wp and bp do not share slots,
    we create another watchpoint to ensure
    the slot accounting is correct

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Milind Chabbi <chabbi.milind@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Oleg Nesterov <onestero@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/20180312134548.31532-9-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>