Please review 6938627: Make temporary directory use property java.io.tmpdir when specified

[Coleen Phillimore]

Summary: Get java.io.tmpdir property in os::get_temp_directory() and 
call this instead of harcoding "/tmp".  Don't assume trailing 
file_separator either.

open webrev at http://cr.openjdk.java.net/~coleenp/6938627/
bug link at http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6938627

Thanks,
Coleen