Update and Bugfix for pexsi/package.py (#8822)
Update and Bugfix for pexsi/package.py (#8822)

* Update and Bugfix for pexsi/package.py

1. pexsi@0.10.2 is not compatible with superlu-dist@5.4.0 due to [Change LargeDiag to LargeDiag_MC64; Add LargeDiag_AWPM](https://github.com/xiaoyeli/superlu_dist/commit/d7dce5a3488f80645023ab8431d82399e5546ebf).
2. In the 'edit' phase, '@MPICXX_LIB' must be substituted before '@MPICXX' is substituted.

* change dict to list of tuples

Use a list of tuples to remember the order of `substitutions`.

* Update package.py

* Update package.py

iulian787/spack,krafczyk/spack,krafczyk/spack,LLNL/spack,mfherbst/spack,mfherbst/spack,LLNL/spack,iulian787/spack,mfherbst/spack,iulian787/spack,LLNL/spack,iulian787/spack,krafczyk/spack,krafczyk/spack,mfherbst/spack,LLNL/spack,LLNL/spack,iulian787/spack,krafczyk/spack,mfherbst/spack