C2: assert((uint)type <= T_CONFLICT && _zero_type[type] != nullptr) failed: bad type with -XX:-UseCompressedClassPointers

Running test/hotspot/jtreg/compiler/c2/irTests/scalarReplacement/AllocationMergesTests.java with -XX:-UseCompressedClassPointers results in the following assertion failure.

This starts to happen after JDK-8316991.

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/opt/mach5/mesos/work_dir/slaves/0db9c48f-6638-40d0-9a4b-bd9cc7533eb8-S10207/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/74979b04-ad1b-480a-bf47-74c960c8b7c8/runs/51f3ccd6-5237-43fb-bdcb-78484c030f84/workspace/open/src/hotspot/share/opto/type.hpp:412), pid=2189604, tid=2189678
# assert((uint)type <= T_CONFLICT && _zero_type[type] != nullptr) failed: bad type
#
# JRE version: Java(TM) SE Runtime Environment (23.0+20) (fastdebug build 23-ea+20-1590)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 23-ea+20-1590, mixed mode, tiered, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x1521ccc] PhaseValues::zerocon(BasicType)+0xbc
..........
Command Line: -DReproduce=true -Djava.library.path=. -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Dir.framework.server.port=43999 -XX:+UnlockDiagnosticVMOptions -XX:+ReduceAllocationMerges -XX:-BackgroundCompilation -XX:-UseCompressedClassPointers compiler.lib.ir_framework.test.TestVM compiler.c2.irTests.scalarReplacement.AllocationMergesTests
..........
Current CompileTask:
C2:1561 1266 b 4 compiler.c2.irTests.scalarReplacement.AllocationMergesTests::testLoadNarrowKlass_C2 (6 bytes)

Stack: [0x00007530051fe000,0x00007530052fe000], sp=0x00007530052f8670, free space=1001k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x1521ccc] PhaseValues::zerocon(BasicType)+0xbc (type.hpp:412)
V [libjvm.so+0xba80ad] ConnectionGraph::split_castpp_load_through_phi(Node*, Node*, Node*, GrowableArray<Node*>*, GrowableArray<Node*>&)+0x6d
V [libjvm.so+0xbaa825] ConnectionGraph::reduce_phi_on_castpp_field_load(Node*, GrowableArray<Node*>&, GrowableArray<Node*>&)+0x405
V [libjvm.so+0xbaaf55] ConnectionGraph::reduce_phi(PhiNode*, GrowableArray<Node*>&, GrowableArray<Node*>&)+0x465
V [libjvm.so+0xbae053] ConnectionGraph::split_unique_types(GrowableArray<Node*>&, GrowableArray<ArrayCopyNode*>&, GrowableArray<MergeMemNode*>&, Unique_Node_List&)+0x603
V [libjvm.so+0xbb9421] ConnectionGraph::compute_escape()+0x2081
V [libjvm.so+0xbb9c11] ConnectionGraph::do_analysis(Compile*, PhaseIterGVN*)+0xf1
V [libjvm.so+0x9e452a] Compile::Optimize()+0x63a
V [libjvm.so+0x9e8380] Compile::Compile(ciEnv*, ciMethod*, int, Options, DirectiveSet*)+0x1b50
V [libjvm.so+0x83d295] C2Compiler::compile_method(ciEnv*, ciMethod*, int, bool, DirectiveSet*)+0x1d5
V [libjvm.so+0x9f4218] CompileBroker::invoke_compiler_on_method(CompileTask*)+0x928
V [libjvm.so+0x9f4ea8] CompileBroker::compiler_thread_loop()+0x478
V [libjvm.so+0xe9bd6c] JavaThread::thread_main_inner()+0xcc
V [libjvm.so+0x17ae846] Thread::call_run()+0xb6
V [libjvm.so+0x1498bb7] thread_native_entry(Thread*)+0x127