MINOR: intops: add a pair of functions to check multi-byte ranges

MINOR: intops: add a pair of functions to check multi-byte ranges

These new functions is_char4_outside() and is_char8_outside() are meant
to be used to verify if any of the 4 or 8 chars represented respectively
by a uint32_t or a uint64_t is outside of the min,max byte range passed
in argument. This is the simplified, fast version of the function so it
is restricted to less than 0x80 distance between min and max (sufficient
to validate chars). Extra functions are also provided to check for min
or max alone as well, with the same restriction.

The use case typically is to check that the output of read_u32() or
read_u64() contains exclusively certain bytes.