ORC-496: [C++] Fix integer overflow in skip of column reader (#389)
ORC-496: [C++] Fix integer overflow in skip of column reader (#389)

skip() function is the StringDirectColumnReader and DoubleColumnReader
use size_t to compute total size to skip; however, the value is casted
to int when calling underlying input stream.
omalley/orc,omalley/orc,omalley/orc,apache/orc,apache/orc,apache/orc,apache/orc,omalley/orc,apache/orc,apache/orc,omalley/orc,omalley/orc,apache/orc,apache/orc,omalley/orc