dump() batches float tokens of 16 or 17 digits with at least 8 fraction
digits. A damaged image loaded with image_check::bounds can record a
token with no digit before the point and 17 after it, which no JSON
number has. Its q = -17 is outside the range of locate_token(), which
then read fives[17] past its 17 entries; on x86-64 the resulting digits
had 18 digits and failed the assertion of write_decimal() (OSS-Fuzz
issue 583898810, json_view_image_fuzzer).
The batch now takes 8 to 16 fraction digits, which every valid token of
16 or 17 digits has, so it batches the same tokens of valid documents.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Niels Lohmann
5901d861ff