IMPALA-2350: malformed tuples in buffered-tuple-stream-test
IMPALA-2350: malformed tuples in buffered-tuple-stream-test

The buffered tuple stream tests wrote out the memory for integer tuples
as a contiguous array of 4-byte integers, neglecting null indicators.
The same bad assumption was present in both the read and write code,
so the test passed in many circumstances. However, buffer overruns were
sometimes detected in the ASAN build. This bug was present for a long
time but a recent change made the ASAN build fail consistently.
IMPALA-1688, an unexplained failure in buffered-tuple-stream-test may
have the same cause.

This fix also changes the integers written out so that they are not all
small positive integers with many zero bytes.

Change-Id: I4a158751e8a9c934c912831032e83ec85056f06e
Reviewed-on: http://gerrit.cloudera.org:8080/876
Reviewed-by: Tim Armstrong <2f8e34250f03a653da3dc27f7ec203eafdde80fc@cloudera.com>
Tested-by: Internal Jenkins

XiaominZhang/Impala,cchanning/Impala,kapilrastogi/Impala,cchanning/Impala,kapilrastogi/Impala,XiaominZhang/Impala,XiaominZhang/Impala,XiaominZhang/Impala,kapilrastogi/Impala,cchanning/Impala,kapilrastogi/Impala,bratatidas9/Impala-1,bowlofstew/Impala,bowlofstew/Impala,kapilrastogi/Impala,kapilrastogi/Impala,XiaominZhang/Impala,cchanning/Impala,cchanning/Impala,cchanning/Impala,XiaominZhang/Impala,bowlofstew/Impala,kapilrastogi/Impala,XiaominZhang/Impala,bratatidas9/Impala-1,bratatidas9/Impala-1,cchanning/Impala,bowlofstew/Impala,bowlofstew/Impala,bratatidas9/Impala-1,bratatidas9/Impala-1,bowlofstew/Impala,bowlofstew/Impala,bratatidas9/Impala-1,bratatidas9/Impala-1