Fix web-image PlatformThreads override

Author: thomaswue

web-image/src/com.oracle.svm.webimage/src/com/oracle/svm/webimage/threads/WebImageJSJavaThreads.java

@@ -47,7 +47,7 @@
 public class WebImageJSJavaThreads extends PlatformThreads {
 
     @Override
-    protected boolean doStartThread(Thread thread, long stackSize, long parentThreadId, String parentVThreadName) {
+    protected boolean doStartThread(Thread thread, long stackSize) {
         // Not supported
         return false;
     }