Fix flaky memory metrics test
Fix flaky memory metrics test

A test checks whether the tcmalloc 'bytes in use' counter goes up after
an allocation. However, tcmalloc may choose to return some bytes to the
heap during that allocation, and so the absolute value might not always
go up. This patch just makes the allocation size much larger, so that it
dwarfs the amount of memory potentially freed by tcmalloc.

Change-Id: I2dd31d28e033f30fcd1090d15853a60d070f4d8e
Reviewed-on: http://gerrit.cloudera.org:8080/288
Reviewed-by: Henry Robinson <3eca10f30041813f045165784e24b5a950a6cc7e@cloudera.com>
Tested-by: Internal Jenkins

ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC