Add support to detect prefixed JAVA_HOME_ env variables for installation

[laeubi]

The setup-java github actions defines by default java installations in env variable starting with JAVA_HOME_ but this is currently not detected.

This now additionally also supports this form of JVM installs and fixes an issue with relying on toSet returning a modifiable set (what is not guaranteed).

What it does

How to test

Author checklist

• I have thoroughly tested my changes
• The change is following the coding conventions
• I have signed the Eclipse Contributor Agreement (ECA)

[eclipse-jdt-bot]

This pull request changes some projects for the first time in this development cycle.
Therefore the following files need a version increment:

org.eclipse.jdt.launching/META-INF/MANIFEST.MF
org.eclipse.jdt.launching/pom.xml

An additional commit containing all the necessary changes was pushed to the top of this PR's branch. To obtain these changes (for example if you want to push more changes) either fetch from your fork or apply the git patch.

Git patch

From 16d13948795c64ac27ec41e17dfae4c359c63395 Mon Sep 17 00:00:00 2001
From: Eclipse JDT Bot <jdt-bot@eclipse.org>
Date: Mon, 1 Sep 2025 12:39:50 +0000
Subject: [PATCH] Version bump(s) for 4.38 stream


diff --git a/org.eclipse.jdt.launching/META-INF/MANIFEST.MF b/org.eclipse.jdt.launching/META-INF/MANIFEST.MF
index 4328838ba..78aef56ea 100644
--- a/org.eclipse.jdt.launching/META-INF/MANIFEST.MF
+++ b/org.eclipse.jdt.launching/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.jdt.launching; singleton:=true
-Bundle-Version: 3.23.400.qualifier
+Bundle-Version: 3.23.500.qualifier
 Bundle-Activator: org.eclipse.jdt.internal.launching.LaunchingPlugin
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
diff --git a/org.eclipse.jdt.launching/pom.xml b/org.eclipse.jdt.launching/pom.xml
index 436996f6d..83f98ceb7 100644
--- a/org.eclipse.jdt.launching/pom.xml
+++ b/org.eclipse.jdt.launching/pom.xml
@@ -18,7 +18,7 @@
   </parent>
   <groupId>org.eclipse.jdt</groupId>
   <artifactId>org.eclipse.jdt.launching</artifactId>
-  <version>3.23.400-SNAPSHOT</version>
+  <version>3.23.500-SNAPSHOT</version>
   <packaging>eclipse-plugin</packaging>
   
   <build>
-- 
2.51.0

Further information are available in Common Build Issues - Missing version increments.

[akurtakov]

Looks good.