Add option to redirect stdout from tests to a file

Instead of

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T E S T S
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Running org.apache.maven.wagon.providers.webdav.WebDavWagonTest
17:59:47.546 EVENT Stopping Acceptor ServerSocket[addr=0.0.0.0/0.0.0.0,port=0,localport=10007]
17:59:47.546 EVENT Stopped SocketListener on 0.0.0.0:10007
17:59:47.546 EVENT Stopped ServletHttpContext[/dav]
17:59:47.546 EVENT Stopped org.mortbay.jetty.Server@b307f0
Tests run: 4, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 1.406 sec

show just

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T E S T S
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Running org.apache.maven.wagon.providers.webdav.WebDavWagonTest
Tests run: 4, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 1.406 sec