[TESTBUG] jvmti_FollowRefObjects.cpp missing initializer for member _jvmtiHeapCallbacks::heap_reference_callback

Error when linking the JVMTI native tests with the gold linker:

* For target support_test_hotspot_jtreg_native_support_libsetsysprop002_libsetsysprop002.o:
In file included from /home/iklam/jdk/blu/open/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetSystemProperty/setsysprop002/libsetsysprop002.cpp:29:0:
/home/iklam/jdk/blu/open/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp:38:44: error: missing initializer for member '_jvmtiHeapCallbacks::heap_iteration_callback' [-Werror=missing-field-initializers]
 jvmtiHeapCallbacks g_wrongHeapCallbacks = {};
                                            ^
/home/iklam/jdk/blu/open/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp:38:44: error: missing initializer for member '_jvmtiHeapCallbacks::heap_reference_callback' [-Werror=missing-field-initializers]
/home/iklam/jdk/blu/open/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp:38:44: error: missing initializer for member '_jvmtiHeapCallbacks::primitive_field_callback' [-Werror=missing-field-initializers]
/home/iklam/jdk/blu/open/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp:38:44: error: missing initializer for member '_jvmtiHeapCallbacks::array_primitive_value_callback' [-Werror=missing-field-initializers]
/home/iklam/jdk/blu/open/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp:38:44: error: missing initializer for member '_jvmtiHeapCallbacks::string_primitive_value_callback' [-Werror=missing-field-initializers]
/home/iklam/jdk/blu/open/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp:38:44: error: missing initializer for member '_jvmtiHeapCallbacks::reserved5' [-Werror=missing-field-initializers]
/home/iklam/jdk/blu/open/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp:38:44: error: missing initializer for member '_jvmtiHeapCallbacks::reserved6' [-Werror=missing-field-initializers]
/home/iklam/jdk/blu/open/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp:38:44: error: missing initializer for member '_jvmtiHeapCallbacks::reserved7' [-Werror=missing-field-initializers]
/home/iklam/jdk/blu/open/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp:38:44: error: missing initializer for member '_jvmtiHeapCallbacks::reserved8' [-Werror=missing-field-initializers]
   ... (rest of output omitted)