perf test: Do not set TEST_SKIP for record subtests

It now has 4 sub tests and at least one of them should run.

But once the TEST_SKIP (= 2) return value is set, it won't be
overwritten unless there's a failure. I think we should return success
when one or more tests are skipped but the remaining subtests are
passed.

So update the test code not to set the err variable when it skips
the test.

Reviewed-by: Adrian Hunter <[e-mail]>
Signed-off-by: Namhyung Kim <[e-mail]>
Acked-by: Ian Rogers <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/tests/shell/record.sh

···
   if ! perf record -o /dev/null --quiet ${testprog} 2> /dev/null
   then
     echo "Per-thread record [Skipped event not supported]"
-    if [ $err -ne 1 ]
-    then
-      err=2
-    fi
     return
   fi
   if ! perf record --per-thread -o "${perfdata}" ${testprog} 2> /dev/null
···
   if ! perf list | grep -q 'br_inst_retired.near_call'
   then
     echo "Register capture test [Skipped missing event]"
-    if [ $err -ne 1 ]
-    then
-      err=2
-    fi
     return
   fi
   if ! perf record --intr-regs=\? 2>&1 | grep -q 'available registers: AX BX CX DX SI DI BP SP IP FLAGS CS SS R8 R9 R10 R11 R12 R13 R14 R15'
···
   if ! perf record -aB --synth=no -o "${perfdata}" ${testprog} 2> /dev/null
   then
     echo "System-wide record [Skipped not supported]"
-    if [ $err -ne 1 ]
-    then
-      err=2
-    fi
     return
   fi
   if ! perf report -i "${perfdata}" -q | grep -q "${testsym}"