build: remove stale java test results before build
build: remove stale java test results before build

This should fix an issue where, if the LINT build runs in a Jenkins workspace
which contains failed Java tests from a previous run, it would accidentally
pick those up as failures on this run.

Change-Id: I1b03847eb19f87dc0fd28f44d249cc2346095219
Reviewed-on: http://gerrit.cloudera.org:8080/3066
Tested-by: Kudu Jenkins
Reviewed-by: Adar Dembo <866ca730bfc7f544e3ebce604ceeba4879f23df0@cloudera.com>

helifu/kudu,EvilMcJerkface/kudu,andrwng/kudu,InspurUSA/kudu,andrwng/kudu,cloudera/kudu,cloudera/kudu,andrwng/kudu,helifu/kudu,InspurUSA/kudu,helifu/kudu,cloudera/kudu,cloudera/kudu,cloudera/kudu,andrwng/kudu,andrwng/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,InspurUSA/kudu,andrwng/kudu,InspurUSA/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,andrwng/kudu,cloudera/kudu,helifu/kudu,helifu/kudu,andrwng/kudu,EvilMcJerkface/kudu,cloudera/kudu,helifu/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,helifu/kudu,EvilMcJerkface/kudu,andrwng/kudu,cloudera/kudu,EvilMcJerkface/kudu,helifu/kudu,cloudera/kudu,InspurUSA/kudu,helifu/kudu