Update JVM_ symbols for JDK 26+4

Author: gilles-duboscq

espresso/src/com.oracle.truffle.espresso.mokapot/include/jvm.h

@@ -497,6 +497,9 @@ JVM_HasReferencePendingList(JNIEnv *env);
 JNIEXPORT void JNICALL
 JVM_WaitForReferencePendingList(JNIEnv *env);
 
+JNIEXPORT jobject JNICALL
+JVM_ReferenceGet(JNIEnv *env, jobject ref);
+
 JNIEXPORT jboolean JNICALL
 JVM_ReferenceRefersTo(JNIEnv *env, jobject ref, jobject o);
 

espresso/src/com.oracle.truffle.espresso.mokapot/mapfile-vers

@@ -373,6 +373,9 @@ SUNWprivate_1.1 {
                 JVM_IsStaticallyLinked;
                 JVM_CreateThreadSnapshot;
 
+                # JDK 26
+                JVM_ReferenceGet;
+
                 # miscellaneous functions
                 jio_fprintf;
                 jio_printf;

espresso/src/com.oracle.truffle.espresso.mokapot/src/mokapot.c

@@ -1663,6 +1663,11 @@ JNIEXPORT jboolean JNICALL JVM_PhantomReferenceRefersTo(JNIEnv *env, jobject ref
   return (*getEnv())->JVM_PhantomReferenceRefersTo(env, ref, o);
 }
 
+JNIEXPORT jobject JNICALL JVM_ReferenceGet(JNIEnv *env, jobject ref) {
+    UNIMPLEMENTED(JVM_ReferenceGet);
+    return NULL;
+}
+
 JNIEXPORT jboolean JNICALL JVM_ReferenceRefersTo(JNIEnv *env, jobject ref, jobject o) {
   IMPLEMENTED(JVM_ReferenceRefersTo);
   return (*getEnv())->JVM_ReferenceRefersTo(env, ref, o);