Remove isolated java wrapper mode

[wkozaczuk]

For reasons explained in #953 (comment), the so-called "isolated" mode of running java apps is a dead-end in modern Java. In short, the "isolated" mode, intended to support running multiple Java apps on OSv by isolating their class loaders and loggers.

The Java version 9 and newer remove certain interfaces like java.util.logging.LogManager.addPropertyChangeListener() and types of class loaders used in the OSv Java code in isolated mode. On top of this, modern Java provides a way to achieve isolation by so-called "isolates" (see https://www.graalvm.org/sdk/javadoc/index.html?org/graalvm/nativeimage/Isolates.html and https://www.graalvm.org/sdk/javadoc/index.html?org/graalvm/nativeimage/Isolates.html). There seems to be also a modern lightweight library that provides some sort of isolation and works with java 11 (I think) - https://github.com/chrisgleissner/jisolate.

Given all that I propose, we kill the java isolated mode. This would entail:

• eliminate modules/java-base/runjava-isolated (possibly collapse modules/java-base/runjava-non-isolated with modules/java-base/runjava-common)
• eliminate the module java-isolated
• update modules/java-base/java.cc to remove isolated-mode specific code
• update modules/java-tests to remove isolated-mode tests
• update scripts/module.py and related scripts to remove isolated-vs-non-isolated code
• eliminate io.osv.isolated.MultiJarLoader and update any Java apps from apps using it
• test