Diagnose failing MPI-IO adapter test

[ChristopherHogan]

The section "write to new file using shared ptr" in the test case "SingleWriteCollective" in mpiio_adapter_basic_test.cpp fails intermittently in CI. I haven't been able to reproduce it locally. It's currently commented out. Failed assertions below.

2021-06-30T19:36:52.1469607Z 32: SingleWriteCollective
2021-06-30T19:36:52.1470099Z 32:   write to new  file using shared ptr
2021-06-30T19:36:52.1470837Z 32: -------------------------------------------------------------------------------
2021-06-30T19:36:52.1471549Z 32: /home/runner/work/hermes/hermes/adapter/test/mpiio/mpiio_adapter_basic_test.cpp:360
2021-06-30T19:36:52.1472109Z 32: ...............................................................................
2021-06-30T19:36:52.1472438Z 32: 
2021-06-30T19:36:52.1472987Z 32: /home/runner/work/hermes/hermes/adapter/test/mpiio/mpiio_adapter_basic_test.cpp:371: FAILED:
2021-06-30T19:36:52.1473962Z 32:   REQUIRE( fs::file_size(info.shared_new_file) == (size_t)test::size_written_orig * info.comm_size )
2021-06-30T19:36:52.1474551Z 32: with expansion:
2021-06-30T19:36:52.1474914Z 32:   65536 (0x10000) == 131072 (0x20000)
2021-06-30T19:36:52.1475207Z 32: 
2021-06-30T19:36:52.1475477Z 32: 
2021-06-30T19:36:52.1475980Z 32: /home/runner/work/hermes/hermes/adapter/test/mpiio/mpiio_adapter_basic_test.cpp:360
2021-06-30T19:36:52.1476559Z 32: ...............................................................................
2021-06-30T19:36:52.1476882Z 32: 
2021-06-30T19:36:52.1477458Z 32: /home/runner/work/hermes/hermes/adapter/test/mpiio/mpiio_adapter_basic_test.cpp:371: FAILED:
2021-06-30T19:36:52.1478310Z 32:   REQUIRE( fs::file_size(info.shared_new_file) == (size_t)test::size_written_orig * info.comm_size )
2021-06-30T19:36:52.1478897Z 32: with expansion:
2021-06-30T19:36:52.1479243Z 32:   65536 (0x10000) == 131072 (0x20000)