performance improvement: reduce time taken by performance test from 7.5 seconds to 2.5 seconds (2 tests, gain=10 seconds)

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1595497 13f79535-47bb-0310-9956-ffa450edef68
performance improvement: sleep not required as rollover is size-driven (speedup of 10 seconds)

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1595500 13f79535-47bb-0310-9956-ffa450edef68
performance improvement: reduce to a single sleep() long enough to trigger a rollover (speedup from 11 to 2.3 seconds)

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1595502 13f79535-47bb-0310-9956-ffa450edef68
migrated the deprecated forkMode parameter to forkCount & reuseForks (http://maven.apache.org/surefire/maven-surefire-plugin/examples/fork-options-and-parallel-execution.html), added memory settings

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1595503 13f79535-47bb-0310-9956-ffa450edef68
performance improvement: changed from reuseForks=false (old setting: forkMode=always) to reuseForks=true (about 8 seconds faster)

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1595504 13f79535-47bb-0310-9956-ffa450edef68
performance improvement: added surefire plugin with reuseForks=true to override parent setting of reuseForks=false (speedup: from 22 to 10.5 seconds)

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1595505 13f79535-47bb-0310-9956-ffa450edef68