CoreJrtFileSystem uses JrtFileSystemProvider provider to read contents
of jrt-fs from JDK
Implementation of FileSystems.newFileSystem causes metaspace memory leak
that wasn't fixed until JDK 17, see
https://bugs.openjdk.java.net/browse/JDK-8260621
When FileSystems.newFileSystem used to create jrt-fs on JDK9 with
provided java.home value it creates new ClassLoader under-the-hood,
which subsequently leaks due to aforementioned bug
Remove conditional usage of `java.home` + FileSystems.newFileSystem and
switch to use jrt-fs classloader cache regardless of
compiler runtime JDK to reduce classloader leaks
^KT-56789
Simon Ogorodnik
253cdb1b8f