HPCC-10097 Regression test javaembed crashing intermittently

I have no proof that it's related to the (unreproducable) occasional crash,
but I did spot that I was not initializing one field passed to the jvm at
startup.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #4883 from richardkchapman/jvm-uninit

HPCC-10097 Regression test javaembed crashing intermittently

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>