perf jevents: Add metric DefaultShowEvents

perf jevents: Add metric DefaultShowEvents

Some Default group metrics require their events showing for
consistency with perf's previous behavior. Add a flag to indicate when
this is the case and use it in stat-display.

As events are coming from Default metrics remove that default hardware
and software events from perf stat.

Following this change the default perf stat output on an alderlake looks like:
```
$ perf stat -a -- sleep 1

 Performance counter stats for 'system wide':

            20,550      context-switches                 #      nan cs/sec  cs_per_second
             TopdownL1 (cpu_core)                 #      9.0 %  tma_bad_speculation
                                                  #     28.1 %  tma_frontend_bound
             TopdownL1 (cpu_core)                 #     29.2 %  tma_backend_bound
                                                  #     33.7 %  tma_retiring
             6,685      page-faults                      #      nan faults/sec  page_faults_per_second
       790,091,064      cpu_atom/cpu-cycles/
                                                  #      nan GHz  cycles_frequency       (49.83%)
     2,563,918,366      cpu_core/cpu-cycles/
                                                  #      nan GHz  cycles_frequency
                                                  #     12.3 %  tma_bad_speculation
                                                  #     14.5 %  tma_retiring             (50.20%)
                                                  #     33.8 %  tma_frontend_bound       (50.24%)
        76,390,322      cpu_atom/branches/               #      nan M/sec  branch_frequency     (60.20%)
     1,015,173,047      cpu_core/branches/               #      nan M/sec  branch_frequency
             1,325      cpu-migrations                   #      nan migrations/sec  migrations_per_second
                                                  #     39.3 %  tma_backend_bound        (60.17%)
              0.00 msec cpu-clock                        #    0.000 CPUs utilized
                                                  #      0.0 CPUs  CPUs_utilized
       554,347,072      cpu_atom/instructions/           #    0.64  insn per cycle
                                                  #      0.6 instructions  insn_per_cycle  (60.14%)
     5,228,931,991      cpu_core/instructions/           #    2.04  insn per cycle
                                                  #      2.0 instructions  insn_per_cycle
         4,308,874      cpu_atom/branch-misses/          #    5.65% of all branches
                                                  #      5.6 %  branch_miss_rate         (49.76%)
         9,890,606      cpu_core/branch-misses/          #    0.97% of all branches
                                                  #      1.0 %  branch_miss_rate

       1.005477803 seconds time elapsed
```

Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>