perf test attr: Fix python SafeConfigParser() deprecation warning

Address the warning:
```
tests/attr.py:155: DeprecationWarning: The SafeConfigParser class has
  been renamed to ConfigParser in Python 3.2. This alias will be
  removed in Python 3.12. Use ConfigParser directly instead.
parser = configparser.SafeConfigParser()
```
by removing the word 'Safe'.
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: https://lore.kernel.org/r/20230517225707.2682235-2-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/attr.py

@@ -152,7 +152,7 @@ def parse_version(version):
 #   - expected values assignments
 class Test(object):
     def __init__(self, path, options):
-        parser = configparser.SafeConfigParser()
+        parser = configparser.ConfigParser()
         parser.read(path)
 
         log.warning("running '%s'" % path)
@@ -247,7 +247,7 @@ class Test(object):
         return True
 
     def load_events(self, path, events):
-        parser_event = configparser.SafeConfigParser()
+        parser_event = configparser.ConfigParser()
         parser_event.read(path)
 
         # The event record section header contains 'event' word,
@@ -261,7 +261,7 @@ class Test(object):
             # Read parent event if there's any
             if (':' in section):
                 base = section[section.index(':') + 1:]
-                parser_base = configparser.SafeConfigParser()
+                parser_base = configparser.ConfigParser()
                 parser_base.read(self.test_dir + '/' + base)
                 base_items = parser_base.items('event')