Reworked setting of bash JAVA_HOME

[Johnny-Malizia]

This change will set JAVA_HOME before a command is executed, not when the prompt is displayed. The difference is subtle but it reduces terminal latency significantly.

I also swapped out the call to asdf which for asdf where to reduce the amount of work necessary to set the JAVA_HOME as the value provided by asdf where provides the correct path.

@halcyon from our discussion earlier, I think this change fits a little better and keeps all existing functionality only reducing the amount of latency added to the terminal.