Read barriers are missing in nmethod printing code

# SIGSEGV (0xb) at pc=0x00007f5c5d7b6630, pid=23724, tid=23755

# Problematic frame:
# V [libjvm.so+0x1503630] oopDesc::print_value_on(outputStream*) const+0xc0

Current CompileTask:
C2: 3263 398 compiler.vectorapi.TestVectorShiftImm::shift_with_op_and_add (167 bytes)

Stack: [0x00007f5a2c9f6000,0x00007f5a2caf7000], sp=0x00007f5a2caf5440, free space=1021k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x1503630] oopDesc::print_value_on(outputStream*) const+0xc0
V [libjvm.so+0x14b76a6] nmethod::reloc_string_for(unsigned char*, unsigned char*)+0x626
V [libjvm.so+0x14b8952] nmethod::decode2(outputStream*) const+0x642
V [libjvm.so+0x14b8d35] nmethod::print_nmethod(bool)+0x3c5
V [libjvm.so+0xa20d36] CompileBroker::invoke_compiler_on_method(CompileTask*)+0x7e6
V [libjvm.so+0xa22118] CompileBroker::compiler_thread_loop()+0x5a8
V [libjvm.so+0x1844891] JavaThread::thread_main_inner()+0x271
V [libjvm.so+0x184cae0] Thread::call_run()+0x100
V [libjvm.so+0x1537036] thread_native_entry(Thread*)+0x116


siginfo: si_signo: 11 (SIGSEGV), si_code: 1 (SEGV_MAPERR), si_addr: 0x0000000000000140