trace_to_text: Handle unusual control characters
trace_to_text: Handle unusual control characters

Give trace_to_text support for \f and other control
characters when converting to systrace and json.

Bug: 137957023
Change-Id: I184b97bdb76b6b67505d080116b94ea76afd29f8

google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto