Remove the use of $HOME

Previously, the killjava script was referenced using $HOME.  This
change removes that usage and instead refers to it relative to the
current working directory.  In addition, some minor improvements were
made so that the directory that the killjava script was placed in, was
not hardcoded.

[#52706435]
Merge 52706435-remove-home to master

[Completes #52706435]