runtime/params: set ompi_mpi_compat_mpi3 to true by default

[wzamazon]

ompi_mpi_compat_mpi3 controls whether MPI default behavior fix MPI-3 standard or MPI-4 standard.

Because the main branch is following MPI-3 standard, this parameter's default value should be true, but it is false prior to this patch

This patch addressed the issue.
Fixes #11809

[jsquyres]

bot:ibm:retest

[jsquyres]

@wzamazon Can you chase down the IBM CI error?

[wzamazon]

The output of IBM CI (ppc64le, GNU) is as the following.

CI Test Results:
---------------------------------------------------------------------------
                     Date : Tue Jul 11 18:31:57 UTC 2023
                 Hostname : ci-ompi-gnu-upstream-cluster-login-9tngq
                       OS : Red Hat Enterprise Linux release 8.6 (Ootpa)
          Virtual Cluster : Number of Nodes = 5
               C Compiler : gcc (GCC) 8.5.0 20210514 (Red Hat 8.5.0-10)
         Fortran Compiler : GNU Fortran (GCC) 8.5.0 20210514 (Red Hat 8.5.0-10)
       Autogen (Open MPI) : ./autogen.pl
                          : Passed [0] (02:32)
     Configure (Open MPI) : ./configure --prefix=/opt/ci/support/exports/ompi --disable-cuda --disable-nvml --with-cuda=no --without-hcoll
                          : Passed [0] (07:18)
          Make (Open MPI) : make -j 20
                          : Passed [0] (04:40)
  Make Install (Open MPI) : make -j 20 install
                          : Passed [0] (00:58)
      ---- Unit Test ---- : examples/hello_c
          Build (hello_c) : make hello_c
                          : Passed [0] (00:00)
            Run (hello_c) : mpirun --hostfile /opt/mpi/etc/hostfile --map-by ppr:4:node --mca btl_tcp_if_include eth0 --mca oob_tcp_if_include eth0 hello_c
                          : Failed [1] (10:00)
---------------------------------------------------------------------------
mpicc -g  hello_c.c  -o hello_c

which is not very helpful. Can someone who is familiar with IBM CI help?

[wzamazon]

bot:ibm:retest

[jsquyres]

@wzamazon Do we document ompi_mpi_compat_mpi3 in the docs anywhere? If not, could you add a blurb somewhere, perhaps somewhere around where we discuss Open MPI's level of MPI conformance?