perf, tools, test: Add test case for alias and JSON parsing

Add a simple test case to perf test that parses all the available
events, including json events.

This needs adding an all event iterator to pmu.c

v2: Rename identifiers
v3: Only iterate cpu pmu to avoid bogus errors.
Move pmu iterator to extra patch
v4: Include aliases.c again
v5: Include util/debug.h
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>