Fix downloading jdk AZUL 8 in Bash script

[djeang]

Current Problem Description

Jeka succeed at extracting JDK having the following structure.

.
├── root-entry-dir
│           ├── bin
│               ├── javac
                ├─── java

Azul 8 and some other distributions seem to add an additional folder level between the root-entry-dir and bin.

We need to handle this case properly in the Jeka shell script.

Testing Instructions:

1. Run the script with the following argument:

   jeka -Djeka.java.distribution=azul -Djeka.java.version=8