read: Fix double validation and infinity parsing
read: Fix double validation and infinity parsing

The ',' protocol byte gets removed in processItem(), so it should not
be compared against in processLineItem().

strtod() allows multiple representations of infinity and NaN that are
not RESP3 compliant. Since we explicitly check for the two compliant
infinity cases, strtod() should only return finite values.

redis/hiredis,redis/hiredis,redis/hiredis