Changes from Mercurial (hg http://isabelle.in.tum.de/repos/isabelle/ default)
Summary
- clarified exception: avoid odd compiler warning;
- update to scala-3.2.1; enforce rebuild of Isabelle/ML + Isabelle/Scala;
- recovered check from 69139cc01ba1: Windows does not support PosixFilePermission;
- update to jdk-17.0.5 (Oct-2022);
- more standard component build process;
- proper treatment of tar.gz double-extension;
- proper download, instead of assuming local directory;
- more standard component build process;
- clarified signature; omit somewhat pointless test for "unzip" command;
- clarified signature; tuned messages;
- discontinue unused JCEF: superseded by Electron with its bundled Chromium;
- prefer deterministic result;