I saw this assert in my dev branch for CAS based allocator, but I also managed to reproduce with TIP of master branch, hence I believe it is bug in TIP.

I only saw this assert on X86 so far, never saw it on aarch64:

```
#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/home/xlpeng/repos/jdk-xlpeng/src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.cpp:92), pid=30813, tid=30860
# assert(!ReduceInitialCardMarks || !ShenandoahCardBarrier || ShenandoahGenerationalHeap::heap()->is_in_young(new_obj)) failed: Allocating new object outside of young generation: 0x0000000745d8cb30
#
# JRE version: OpenJDK Runtime Environment (26.0) (fastdebug build 26-internal-adhoc.xlpeng.jdk-xlpeng)
# Java VM: OpenJDK 64-Bit Server VM (fastdebug 26-internal-adhoc.xlpeng.jdk-xlpeng, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, shenandoah gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x190291a] ShenandoahBarrierSet::on_slowpath_allocation_exit(JavaThread*, oop)+0x13a
#
# No core dump will be written. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp

```

How to produce it?
Simply repeat test vmTestbase/vm/gc/concurrent/lp30yp25rp30mr70st0/TestDescription.java, the error will show up eventually:
```
CONF=linux-x86_64-server-fastdebug TEST=vmTestbase/vm/gc/concurrent/lp30yp25rp30mr70st0/TestDescription.java JTREG_REPEAT_COUNT=10000 make test
```