Trivial link error when building with gcc 15.2 on Fedora.

```
* For target hotspot_variant-server_libjvm_gtest_objs_BUILD_GTEST_LIBJVM_run_ld:
/usr/bin/ld: /shared/projects/openjdk/valhalla/output-release/hotspot/variant-server/libjvm/gtest/objs/test_flatArrayOop.o: in function `ensure_no_overflow(flatArrayOopDesc*, int) [clone .constprop.0]':
make/hotspot/test/hotspot/gtest/oops/test_flatArrayOop.cpp:50:(.text+0x2f): undefined reference to `flatArrayOopDesc::value_at_addr(int, int) const'
/usr/bin/ld: make/hotspot/test/hotspot/gtest/oops/test_flatArrayOop.cpp:52:(.text+0x50): undefined reference to `flatArrayOopDesc::value_at_addr(int, int) const'
```