Set GRAALVM_HOME for GraalVM distributions (#1146)

* Initial plan

* Set GRAALVM_HOME for GraalVM distributions

* Rebuild setup action bundle

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

src/distributions/graalvm/installer.ts

@@ -110,6 +110,11 @@ export class GraalVMDistribution extends JavaBase {
     }
   }
 
+  protected setJavaDefault(version: string, toolPath: string): void {
+    super.setJavaDefault(version, toolPath);
+    core.exportVariable('GRAALVM_HOME', toolPath);
+  }
+
   protected async findPackageForDownload(
     range: string
   ): Promise<JavaDownloadRelease> {