Performance degradation from 4.0.7 to 5.0.1 to 5.1.1

I have noticed a performance degradation from 4.0.7 to 5.0.1, and 5.0.1 to 5.1.1. Both in creating new StatelessSessions, and executing them.

I am attaching a portable test case which shows the degradation. Please refer to the test.zip!/README.txt file for full instructions and explanation.

For the purpose of this jira description (and to show the degradation from a high-level), here is sample output. Note that the run*.sh scripts only create new StatelessSessions, but do not execute them. The exec*.sh scripts also execute the StatelessSessions.

run407.sh
RuleTest: count=10000, total=33ms, average=0.0033ms
KnowledgeTest: API not available

run501.sh
RuleTest: count=10000, total=1147ms, average=0.1147ms
KnowledgeTest: count=10000, total=784ms, average=0.0784ms

run511.sh
RuleTest: count=10000, total=2381ms, average=0.2381ms
KnowledgeTest: count=10000, total=2007ms, average=0.2007ms

exec407.sh
RuleTest: count=10000, total=875ms, average=0.0875ms
KnowledgeTest: API not available

exec501.sh
RuleTest: count=10000, total=2641ms, average=0.2641ms
KnowledgeTest: count=10000, total=2223ms, average=0.2223ms

exec511.sh
RuleTest: count=10000, total=4188ms, average=0.4188ms
KnowledgeTest: count=10000, total=3664ms, average=0.3664ms