perf test: Add 30s timeout for wait for daemon start.

Retry the ping loop upto 600 times, or approximately 30 seconds, to make
sure the test does hang at start up.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@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: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210317005505.2794804-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>