lisa.trace: Fix HRTxtTraceParser regex parsing

FIX

A Systrace generated by the Perfetto's traceconv tool has records with this
format:
```
    <idle>-0     (-----) [000] .... 608397.919018: sched_wakeup: comm=traced pid=403293 prio=120 target_cpu=000
 ```
which timestamp gets parsed as `7.919018`, i.e. by ignoring all the digits but
one decimal.

The regexp also picks up all the spaces before the task name, by ending up with
duplicated names when the same task name is parsed also (without space) form an
event field (e.g. a `sched_switch`'s `next_comm`)

Fix the timestamp parsing by ensuring that, after the `__cpu` filed has been
parsed, we skip all and only the non digit chars following it.
Fix the command name parsing by ensuring we discard all the space before the
name start.