JDK_HOME can be sorted after lower-priority auto-detected JDK sources

[shblue21]

Describe the bug
When the Java home settings are not set, a JDK configured through JDK_HOME may not be listed first if another JDK is also detected from JAVA_HOME or PATH.

JDK_HOME seems to be intended as the highest-priority source.

To Reproduce

1. Leave java.jdt.ls.java.home, java.home, and java.configuration.runtimes unset.
2. Make sure java.configuration.detectJdksAtStart is enabled.
3. Configure JDK_HOME with one valid JDK.
4. Configure JAVA_HOME, or PATH, with a different valid JDK.
5. Restart VS Code.
6. Open Java: Configure Java Runtime and check the detected JDK order.

Actual behavior
The JDK from JDK_HOME may appear after the other detected JDK.

Expected behavior
The JDK from JDK_HOME should appear first.

Environment

• Operating System: macOS
• JDK version: JDK 17 from JDK_HOME, JDK 25 from JAVA_HOME
• Visual Studio Code version: 1.125.0-insider
• Java extension version: 1.55.0

Additional Information
sortJdksBySource() gives JDK_HOME rank 0, but the later rank check does not treat 0 as an assigned rank.