Add ARRAY_SIZE macro, and use it where possible.

py/builtin.c

py/builtintables.c

py/compile.c

py/emitinlinethumb.c

py/misc.h

py/modarray.c

py/modcmath.c

py/modcollections.c

py/modio.c

py/modmath.c

py/modmicropython.c

py/modstruct.c

py/modsys.c

stmhal/dac.c

stmhal/extint.c

stmhal/i2c.c

stmhal/led.c

stmhal/main.c

stmhal/modos.c

stmhal/modpyb.c