ThirdPartyAuditTask - Add vector module when building with JDK 21 (elastic#96949)

This commit extends the ThirdPartyAuditTask check that adds the vector module when building, to include JDK 21.

This is needed now as Lucene has added support for the VectorUtilPanamaProvider with JDK 21. We want to keep the check to very specific versions / ranges, that match that of Lucene.

Author: ChrisHegarty

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/precommit/ThirdPartyAuditTask.java

@@ -58,6 +58,7 @@
 import javax.inject.Inject;
 
 import static org.gradle.api.JavaVersion.VERSION_20;
+import static org.gradle.api.JavaVersion.VERSION_21;
 
 @CacheableTask
 public abstract class ThirdPartyAuditTask extends DefaultTask {
@@ -337,8 +338,8 @@ private String runForbiddenAPIsCli() throws IOException {
                 spec.setExecutable(javaHome.get() + "/bin/java");
             }
             spec.classpath(getForbiddenAPIsClasspath(), classpath);
-            // Enable explicitly for each release as appropriate. Just JDK 20 for now, and just the vector module.
-            if (isJava20()) {
+            // Enable explicitly for each release as appropriate. Just JDK 20/21 for now, and just the vector module.
+            if (isJavaVersion(VERSION_20) || isJavaVersion(VERSION_21)) {
                 spec.jvmArgs("--add-modules", "jdk.incubator.vector");
             }
             spec.jvmArgs("-Xmx1g");
@@ -363,13 +364,13 @@ private String runForbiddenAPIsCli() throws IOException {
         return forbiddenApisOutput;
     }
 
-    /** Returns true iff the Java version is 20. */
-    private boolean isJava20() {
+    /** Returns true iff the build Java version is the same as the given version. */
+    private boolean isJavaVersion(JavaVersion version) {
         if (BuildParams.getIsRuntimeJavaHomeSet()) {
-            if (VERSION_20.equals(BuildParams.getRuntimeJavaVersion())) {
+            if (version.equals(BuildParams.getRuntimeJavaVersion())) {
                 return true;
             }
-        } else if ("20".equals(VersionProperties.getBundledJdkMajorVersion())) {
+        } else if (version.getMajorVersion().equals(VersionProperties.getBundledJdkMajorVersion())) {
             return true;
         }
         return false;