Crash creating offline trace for Grazelle

```
pebraun$ ./dynamorio/build/bin64/drrun -t drmemtrace -offline -trace_after_instrs 1M -exit_after_tracing 10G -- ~/Grazelle-PPoPP18/output/linux/grazelle -i ~/Grazelle-PPoPP18/cit-Patents.bin
Experiments: THRESHOLD_WITHOUT_COUNT
Hit delay threshold: enabling tracing.
In-edges: created 5687755 vectors, efficiency = 72.6%
Out-edges: created 4940362 vectors, efficiency = 83.6%
Vertices: assigned using in-edge list
Vertices: node 0 gets 3774768 vertices (0 to 3774767, 100.00% of total)
Scheduler: total units = 896, vectors per unit = 6347
Loading graph took 10568.08ms.
Starting execution.

```

[For reference Grazelle is from https://github.com/stanford-mast/Grazelle-PPoPP18 and compiled with make fig13. The input dataset is from https://zenodo.org/record/1169388 -> both cit-Patents.bin-push and cit-Patents.bin-pull need to be downloaded]

No source file or test is identified in the report. Start by reproducing the exact drrun -t drmemtrace -offline command against Grazelle with the cited dataset, then investigate the reported internal crash at PC 0x00007f11fec7e50c; done means the trace completes without the DynamoRIO tracer aborting.

Written by the indexing model from the issue text.