py: Make compiler return a proper exception on SyntaxError.

bare-arm/main.c

py/builtinevex.c

py/builtinimport.c

py/compile.c

qemu-arm/main.c

qemu-arm/test_main.c

stmhal/pyexec.c

tests/basics/builtin_eval.py

tests/basics/builtin_eval_error.py

unix-cpy/main.c