trace-cmd: updating sched_switch parser to handle both formats.

Depending on the kernel, sched_switch events may be formatted one of two
different ways in the text output. Previously, we've only handled the
"old" format. This commit updates the parser to handle the new format as
well.

wlauto/utils/trace_cmd.py

@@ -173,6 +173,24 @@ def regex_body_parser(regex, flags=0):
     return regex_parser_func
 
 
+def sched_switch_parser(event, text):
+    """
+    Sched switch output may be presented in a couple of different formats. One is handled
+    by a regex. The other format can *almost* be handled by the default parser, if it
+    weren't for the ``==>`` that appers in the middle.
+    """
+    if text.count('=') == 2:  # old format
+        regex = re.compile(
+            r'(?P<prev_comm>\S.*):(?P<prev_pid>\d+) \[(?P<prev_prio>\d+)\] (?P<status>\S+)'
+            r' ==> '
+            r'(?P<next_comm>\S.*):(?P<next_pid>\d+) \[(?P<next_prio>\d+)\]'
+        )
+        parser_func = regex_body_parser(regex)
+        return parser_func(event, text)
+    else:  # three are more than two "=" -- new format
+        return default_body_parser(event, text.replace('==>', ''))
+
+
 # Maps event onto the corresponding parser for its body text. A parser may be
 # a callable with signature
 #
@@ -182,11 +200,7 @@ def regex_body_parser(regex, flags=0):
 # regex). In case of a string/regex, its named groups will be used to populate
 # the event's attributes.
 EVENT_PARSER_MAP = {
-    'sched_switch': re.compile(
-        r'(?P<prev_comm>\S.*):(?P<prev_pid>\d+) \[(?P<prev_prio>\d+)\] (?P<status>\S+)'
-        r' ==> '
-        r'(?P<next_comm>\S.*):(?P<next_pid>\d+) \[(?P<next_prio>\d+)\]'
-    ),
+    'sched_switch': sched_switch_parser,
 }
 
 TRACE_EVENT_REGEX = re.compile(r'^\s+(?P<thread>\S+.*?\S+)\s+\[(?P<cpu_id>\d+)\]\s+(?P<ts>[\d.]+):\s+'