Remove GTL variant from packages

[pearce8]

Follow on the #1136.

Need to remove special mods that override the upstreamed packages. llnl/elcap is a model where the system sets the dependence on GTL, so for specific benchmarks/libraries the dependence on GTL-specific cray-mpich needs to be removed.

• commbench @nhanford
• cray-mpich @scheibelp
• IOR? its in the application.py
• osu-micro-benchmarks @nhanford
• remhos @rfhaque
• sparta-snl @rfhaque
• does Perlmutter need to be updated too? @nhanford @slabasan