Contributed by Steve Loughran.
Replaces the committer-specific terasort and MR test jobs with parameterization
of the (now single tests) and use of file:// over hdfs:// as the cluster FS.
The parameterization ensures that only one of the specific committer tests
run at a time -overloads of the test machines are less likely, and so the
suites can be pulled back into the parallel phase.
There's also more detailed validation of the stage outputs of the terasorting;
if one test fails the rest are all skipped. This and the fact that job
output is stored under target/yarn-${timestamp} means failures should
be more debuggable.
Change-Id: Iefa370ba73c6419496e6e69dd6673d00f37ff095
f44abc3e11