-lg:dump_physical_traces is broken on master for Pennant

[rohany]

Running the following on master:

LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/scratch2/rohany/legion/language/ ./pennant pennant.tests/sedovsmall/sedovsmall.pnt -ll:cpu 4 -npieces 4 -seq_init 1 -par_init 1 -interior 0 -lg:parallel_replay 1 -level tracing=2 -lg:dump_physical_traces

Gives me an error:

[0 - 7fabf774dc40]    0.985402 {2}{tracing}: #### Replayable: Yes, Idempotent: Yes 0x7fabc4ab56a0 Trace 1 for toplevel (UID 2) ####
[0 - 7fabf774dc40]    0.985428 {2}{tracing}: [Slice 0]
pennant: /scratch2/rohany/legion/runtime/legion/legion_trace.cc:10437: virtual std::string Legion::Internal::ReplayMapping::to_string(const MemoEntries&): Assertion `finder != memo_entries.end()' failed.

Looking into this a little bit indicates that the task not being found is https://gitlab.com/StanfordLegion/legion/-/blob/master/language/examples/pennant.rg#L1110, which doesn't take any region arguments, so I suspect that's why it's not getting added to memo_entries. I'm not that familiar with this part of the tracing code (the recording), so handing off.