add self-contained reproducer for restart issue

reproducer.sh

@@ -0,0 +1,32 @@
+#!/bin/sh
+
+set -x
+
+# compile
+mkdir build
+cd build
+cmake .. -DPARTHENON_ENABLE_PYTHON_MODULE_CHECK=OFF
+cmake --build .
+cd ..
+
+# first run
+mpirun -np 8 ./build/bin/athenaPK -i inputs/precipitator_restart_reproducer.in
+
+# move outputs to avoid being overwritten
+mkdir first_run
+mv parthenon.* first_run
+rm *.csv
+
+# restart run
+mpirun -np 8 ./build/bin/athenaPK -r first_run/parthenon.restart.00000.rhdf
+
+# clean up
+rm *.csv
+
+# compare restart outputs
+h5diff first_run/parthenon.restart.00000.phdf parthenon.restart.00001.phdf
+h5diff first_run/parthenon.restart.00001.phdf parthenon.restart.00002.phdf
+
+# compare snapshot outputs
+h5diff first_run/parthenon.prim.00000.phdf parthenon.prim.00001.phdf
+h5diff first_run/parthenon.prim.00001.phdf parthenon.prim.00002.phdf