drcachesim.drstatecmp-fuzz test failed on A64 with invalid instruction

Looks like an error in the instruction synthesis?

http://139.178.84.19:8080/job/DynamoRIO-AArch64-Precommit/824/consoleFull
```
252/255 Test #192: code_api|tool.drcachesim.drstatecmp-fuzz ........................***Failed Required regular expression not found. Regex=[^Generate code
Hit delay threshold: enabling tracing.
Execute generated code
All done
---- ----
.*
$
] 9.14 sec
Generate code
Hit delay threshold: enabling tracing.
Usage error: opnd_create_reg: invalid register (/var/lib/jenkins/workspace/DynamoRIO-AArch64-Precommit/core/ir/instr_inline_api.h, line 209)
```