tests: reduce number of nodes to run tests

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Some tests in SCR and the components currently require multiple compute nodes. While these do need multiple processes, many of these could be modified to run with multiple processes on a single compute node. That should be done so as to reduce the number of resources needed to run the tests.

A common requirement from some tests is to use the hostname to split procs into groups or to define directories. That would need to be modified to perhaps use process ranks instead.

Start by inventorying the SCR and component tests that require multiple compute nodes, then inspect how they use hostnames to split processes or define directories. Done means those tests still run with multiple processes on one node, using process ranks where needed, while preserving their existing behavior.

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