build-and-test.sh: only rerun Spark tests if Java build passes
build-and-test.sh: only rerun Spark tests if Java build passes

Otherwise, the output of a failing Spark test from the first build is
overwritten by the second build.

The alternative is to configure Maven to use a different build directory [1]
for the second build, but I think that's more trouble than it's worth.

1. https://stackoverflow.com/questions/3908013/maven-how-to-change-path-to-target-directory-from-command-line

Change-Id: Ief21061be0615ca4d9d8980430f4982c8c43d77c
Reviewed-on: http://gerrit.cloudera.org:8080/7090
Tested-by: Adar Dembo <866ca730bfc7f544e3ebce604ceeba4879f23df0@cloudera.com>
Reviewed-by: Dan Burkert <4ef91e292a55314d2653d35ff669a6bd939ce515@apache.org>

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