tools/mpy-tool.py: Fix freezing of non-bytecode funcs with settrace.
tools/mpy-tool.py: Fix freezing of non-bytecode funcs with settrace.

Only bytecode functions can be profiled at this stage.  Native functions
(eg inline assembler) may not even have a valid prelude.

Fixes issue #5075.

pfalcon/micropython,pfalcon/micropython,pfalcon/micropython,pfalcon/micropython,pfalcon/micropython