Update nightly test configurations

[prckent]

Proposed changes

Update nightly test configurations. Key changes:

1. Set CMAKE_BUILD_PARALLEL_LEVEL=8 when PySCF involved. Reduces install time for py-pyscf package from e.g. 37 minutes to 7 minutes. By default PySCF will build its substantial C-based components sequentially.
2. Working graphviz "dot" that can produce png files. Enables nexus simulation test to pass.
3. Latest LLVM

What type(s) of changes does this code introduce?

• Testing changes (e.g. new unit/integration/performance tests)

Does this introduce a breaking change?

• No

What systems has this change been tested on?

sulfur, nitrogen, nitrogen2

Checklist

Update the following with a yes where the items apply. If you're unsure about any of them, don't hesitate to ask. This is
simply a reminder of what we are going to look for before merging your code.

• Yes. This PR is up to date with current the current state of 'develop'
• NA. Code added or changed in the PR has been clang-formatted
• NA. This PR adds tests to cover any new code, or to catch a bug that is being fixed
• NA. Documentation has been added (if appropriate)

[ye-luo]

Test this please