fixing some of the problems with nc_test when --enable-pnetcdf is used

[edwardhartnett]

In this PR I tried to pull in a subset of what is in #2020, but without creating a test shell file for each MPI-enabled test, and also continuing to run the MPI-enabled tests (as intended) without mpiexec for non-MPI builds.

Thanks to @tjahns for providing the code to:

• use TEMP_LARGE for pnetcdf tests.
• call MPI_Finalize in test tst_nofill.c
• using @mpiexec@ and a .in file for the test, so that the builder can use a different launcher than mpiexec.

This should be merged (and tests rerun) after #2280, which turns on --enable-pnetcdf testing.

Part of #2283

[ArchangeGabriel]

Seems to me you forgot to take into account CMake builds:

63/258 Testing: nc_test_run_pnetcdf_test
63/258 Test: nc_test_run_pnetcdf_test
Command: "/usr/bin/bash" "-c" "export srcdir=/build/netcdf-openmpi/src/netcdf-c-4.9.0/nc_test;export TOPSRCDIR=/build/netcdf-openmpi/src/netcdf-c-4.9.0;/build/netcdf-openmpi/src/build/nc_test/run_pnetcdf_test.sh run_pnetcdf_test.sh "
Directory: /build/netcdf-openmpi/src/build/nc_test
"nc_test_run_pnetcdf_test" start time: Jun 27 14:13 UTC
Output:
----------------------------------------------------------
/usr/bin/bash: line 1: /build/netcdf-openmpi/src/build/nc_test/run_pnetcdf_test.sh: No such file or directory
<end of output>
Test time =   0.00 sec
----------------------------------------------------------
Test Failed.
"nc_test_run_pnetcdf_test" end time: Jun 27 14:13 UTC
"nc_test_run_pnetcdf_test" time elapsed: 00:00:00
----------------------------------------------------------

I indeed see nothing in this PR generating run_pnetcdf_test.sh from run_pnetcdf_test.sh.in for CMake builds.

[tjahns]

I probably should have stated that earlier: while I have a sufficient grasp of what's needed for autotools builds, I lack the necessary knowledge to extend CMake systems similarly.

[WardF]

I'm working on getting the cmake based build extended :).