ACCUMULO-2138 Backport ACCUMULO-679 to 1.4.x

Original commit message: Fixed the [TabletShouldSplit] test to do a more coherent
check and to produce results more consistently that are accurate. WOrks on my machine,
but may need more love later

git-svn-id: https://svn.apache.org/repos/asf/accumulo/trunk@1359426 13f79535-47bb-0310-9956-ffa450edef68
(cherry picked from commit 06db9a008e1fafb821d57f8bd5c35a7065932030)
ACCUMULO-2152 fix start-all.sh to properly handle multiple gc/tracer roles.

Signed-off-by: Bill Havanki <bhavanki@cloudera.com>
ACCUMULO-2152 Merge branch '1.4.5-SNAPSHOT' into 1.5.1-SNAPSHOT