[lworld] TestLWorld.java fails with "assert(n != __null) failed: must not be null" when executed with -Xcomp

# Internal Error (/scratch/opt/mach5/mesos/work_dir/slaves/14a03e04-9f3c-408e-8ddf-efd6aa9b759f-S85964/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/2005efb2-8b6b-4fa8-9874-5c35e6881c4e/runs/0659f295-b4f0-4608-9490-3abf6be4d5c6/workspace/open/src/hotspot/share/opto/phaseX.hpp:215), pid=30512, tid=30523
# assert(n != __null) failed: must not be null

Current CompileTask:
C2: 47597 1213 b compiler.valhalla.valuetypes.TestLWorld::test66_verifier (10 bytes)

Stack: [0x00007f8a20590000,0x00007f8a20691000], sp=0x00007f8a20689960, free space=998k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x19433e3] VMError::report_and_die(int, char const*, char const*, __va_list_tag*, Thread*, unsigned char*, void*, void*, char const*, int, unsigned long)+0x2c3
V [libjvm.so+0x19441af] VMError::report_and_die(Thread*, void*, char const*, int, char const*, char const*, __va_list_tag*)+0x2f
V [libjvm.so+0xb84290] report_vm_error(char const*, int, char const*, char const*, ...)+0x100
V [libjvm.so+0x18dca74] ValueTypeNode::is_default(PhaseGVN&) const+0x264
V [libjvm.so+0x18dda8a] ValueTypeNode::Ideal(PhaseGVN*, bool)+0x3a
V [libjvm.so+0x15de54e] PhaseGVN::transform_no_reclaim(Node*)+0x4e
V [libjvm.so+0x18df124] ValueTypeNode::make_from_oop(GraphKit*, Node*, ciValueKlass*, bool, bool, int)+0x384
V [libjvm.so+0x1599338] Parse::Parse(JVMState*, ciMethod*, float)+0xf98
V [libjvm.so+0x88829c] ParseGenerator::generate(JVMState*)+0x8c
V [libjvm.so+0x888ef9] LateInlineCallGenerator::do_late_inline()+0x959
V [libjvm.so+0xa8de89] Compile::inline_incrementally_one(PhaseIterGVN&)+0x159
V [libjvm.so+0xa98f2c] Compile::inline_incrementally(PhaseIterGVN&)+0xac
V [libjvm.so+0xa9c24b] Compile::Optimize()+0x26b
V [libjvm.so+0xa9dc6e] Compile::Compile(ciEnv*, C2Compiler*, ciMethod*, int, bool, bool, bool, DirectiveSet*)+0xd6e
V [libjvm.so+0x886391] C2Compiler::compile_method(ciEnv*, ciMethod*, int, DirectiveSet*)+0xd1
V [libjvm.so+0xaab1c9] CompileBroker::invoke_compiler_on_method(CompileTask*)+0x409
V [libjvm.so+0xaac1e7] CompileBroker::compiler_thread_loop()+0x367
V [libjvm.so+0x1858797] JavaThread::thread_main_inner()+0x2c7
V [libjvm.so+0x1858aca] JavaThread::run()+0x22a
V [libjvm.so+0x15360f0] thread_native_entry(Thread*)+0x100