Skip whitespace characters between pairs of hex numbers. This makes `bytes.fromhex()` compatible with cpython. Includes simple test in `tests/basic/builtin_str_hex.py`. Signed-off-by: Glenn Moloney <glenn.moloney@gmail.com>
Also make the sep test not micropython-specific. Signed-off-by: Jim Mussared <jim.mussared@gmail.com>