This may help address #7409 if the underlying cause is the deterministic
volume ID. However, not all boards have working urandom (samd21
at least does not) so a couple of fallbacks are attempted when it fails.
I verified that on a pico_w, each `storage.erase_filesystem()` gives
a distinct 32-bit volume ID (pico_w's urandom can never fail)
This also tweaks the repr for unicode strings to only escape a few
utf-8 code points. This makes emoji show in os.listdir() for
example.
Also, enable exfat support on full builds.
Fixes#5146
.. a requirement that oofatfs needs to be taught to respect.
This problem can be demonstrated with the following snippet, except
that the related file ("test.bin") must also be contiguous on the
filesystem. You can ensure this by reformatting your device's filesystem
before testing, then copying any single file bigger than 4kB to test.bin.
f = open("test.bin", "rb")
f.seek(2048)
b = bytearray(2048)
v = memoryview(b)
f.readinto(v[909:])
Closes: #2332
