Always forget that checking system properties c...
Always forget that checking system properties c...

Always forget that checking system properties causes exceptions in
applets and such. Made the system property wrapper wrap its access
checks in some more wrapping. I spent a long time trying to write a
test for the security manager but it's hopeless without knowing all the
details of the test environment. Closes #4346, no review.


som-snytt/scala-partest,scala/scala-partest,lrytz/scala-partest,SethTisue/scala-partest,scala/scala-partest