Minor Description
In some tests wie spawn separate processes (TestIndexWriterOnJRECrash and Solr's IPTables). To capture stdin/stdout/stderr we spawn several threads that pump those to stdout/stderr.
Since Java 7 there is ProcessBuilder.inheritIO() that does this for us without any additional threads. We should use this instead. Fix is easy, just remove some stuff 
I did the same already for my Codec classloader deadlock test, so this is just a followup for the other tests.
Patch is attached and can be committed to trunk and 5.x.