Amend #4961, bump Java 21. (#4966)

This PR sets the `JAVA_HOME` env variable to `$JAVA_HOME_21_X64` so CMake and Maven picks up the right JVM for native CMake workflows.

Author: gchatelet

.github/workflows/amd64_linux_cmake_java.yml

@@ -32,8 +32,7 @@ jobs:
           sudo apt update
           sudo apt install -y ninja-build ccache swig
           swig -version
-      - name: Check java
-        run: java -version
+          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
 
       # RESTORING CACHES
       - name: Restore CMake dependency source code

.github/workflows/amd64_macos_cmake_java.yml

@@ -38,8 +38,7 @@ jobs:
         run: |
           brew install ccache swig
           swig -version
-      - name: Check java
-        run: java -version
+          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
 
       # RESTORING CACHES
       - name: Restore CMake dependency source code

.github/workflows/arm64_macos_cmake_java.yml

@@ -38,8 +38,7 @@ jobs:
         run: |
           brew install ccache swig
           swig -version
-      - name: Check java
-        run: java -version
+          echo "JAVA_HOME=$JAVA_HOME_21_arm64" >> $GITHUB_ENV
 
       # RESTORING CACHES
       - name: Restore CMake dependency source code