Changes Related to the Auxiliary Process

[raylu-hdf]

This PR is directly related to the PR of the changes in the utils/vfd_swmr submodule: https://github.com/HDFGroup/vfd_swmr_util/pull/1/files

The basic process is like this:

1. The auxiliary process is enabled with the option --enable-aux-process for configure.
2. The test script testvfdswmr.sh launches the auxiliary process with the big set test.
3. If --enable-aux-process isn't enabled, the auxiliary process simply skips itself and exits. The big set test will run by itself.

[kyang2014]

I just browsed the code. Everything looks fine to me. The only thing I don't understand is why the github check fails. This is probably expected since I saw Vailin approve the code already.

[vchoi-hdfgroup]

I also wondered about the github failing checks. I guess Ray will check into the failures.

[raylu-hdf]

I also wondered about the github failing checks. I guess Ray will check into the failures.

The failure happened because this PR tried to check out the CMake and Makefile for the auxiliary process but couldn't. I need to ask Dana why the auxiliary process didn't show up in the submodule after I merged the other PR.