* lisp/profiler.el (profiler-start): Don't prompt for choice when there

* lisp/profiler.el (profiler-start): Don't prompt for choice when there
isn't any.
(profiler-stop): Use new semantics of profiler-*-stop.
(profiler-reset, profiler--report-cpu): Don't signal an error if the
cpu profiler is not available.
* src/profiler.c (Fprofiler_cpu_stop, Fprofiler_memory_stop):
Return whether the profiler was running, instead of signaling an error
if it wasn't.