Add explicit Core/24.00 module to crayclang-scream for Frontier.

[trey-ornl]

OLCF plans to switch defaults for module Core from 24.00 to 24.07. The newer module has a newer version of cmake, and not cmake/3.21.3. The newer cmake is apparently confused by the older style of handling the Cray and AMD compilers. This pull request adds explicit loading of the soon-to-be-previous-default module, Core/24.00, for Frontier build with crayclang-scream. I also changed the version of libunwind to one that is actually available. I think the previous builds quietly failed to load it.

I confirmed that the newer software stack, represented by compiler craygnuamdgpu, works with Core/24.07, so I made no changes to that config.

As an aside, I recommend that all new E3SM runs on Frontier move to craygnuamdgpu.

[E3SM-Bot]

Status Flag 'Pre-Test Inspection' - - This Pull Request Requires Inspection... The code must be inspected by a member of the Team before Testing/Merging
NO INSPECTION HAS BEEN PERFORMED ON THIS PULL REQUEST! - This PR must be inspected by setting label 'AT: PRE-TEST INSPECTED'.

[AaronDonahue]

@ambrad , would you be comfortable reviewing this PR? I believe you reviewed the last frontier machine file change right?

[AaronDonahue]

Adding the skip-testing labels since we don't test on frontier w/ the AT. @trey-ornl already confirmed that this change works on frontier.

[E3SM-Bot]

Status Flag 'Pre-Test Inspection' - SUCCESS: The last commit to this Pull Request has been INSPECTED by label AT: PRE-TEST INSPECTED! Autotester is Removing Label; this inspection will remain valid until a new commit to source branch is performed.