[win-64] All jvm-based kernels fail to start

### Problem
`Groovy`, `Java`, `Scala`, `Clojure`, `Kotlin `kernels fail to start with the following error:

`/lib/ext exists, extensions mechanism no longer supported; Use -classpath instead.`

### Set-up
`win-64`, latest `conda`.

```
py4j=0.10.8.1
pyzmq=17.1.2
zeromq=4.2.5
```
PS A working Linux install features identical package versions.

### Description
`JAVA_HOME` correctly points to within conda environment: `JAVA_HOME=C:\...\envs\beakerx\Library`

There is indeed `README.txt` in `Library\lib\ext`. When removing `ext` folder from `Library\lib` the aforementioned error is superseded with:

`[Thread-0] ERROR KernelSocketsZMQ - java.lang.ExceptionInInitializerError`

### References
1. [Oracle docs](https://docs.oracle.com/javase/9/migrate/toc.htm#JSMIG-GUID-2C896CA8-927C-4381-A737-B1D81D964B7B).
1. https://github.com/twosigma/beakerx/issues/7759.