tracing: Check for printable characters when printing field dyn strings

tracing: Check for printable characters when printing field dyn strings

When the "fields" option is enabled, it prints each trace event field
based on its type. But a dynamic array and a dynamic string can both have
a "char *" type. Printing it as a string can cause escape characters to be
printed and mess up the output of the trace.

For dynamic strings, test if there are any non-printable characters, and
if so, print both the string with the non printable characters as '.', and
the print the hex value of the array.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231148.929243047@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>