Fix bug in coupled interfaces

[Rohit-Kakodkar]

Description

Please describe the changes/features in this pull request.

• Update index function in edge/intersection iterator
• Update for_all execution function

Issue Number

If there is an issue created for these changes, link it here

Checklist

Please make sure to check developer documentation on specfem docs.

• I ran the code through pre-commit to check style
• THE DOCUMENTATION BUILDS WITHOUT WARNINGS/ERRORS
• I have added labels to the PR (see right hand side of the PR page)
• My code passes all the integration tests
• I have added sufficient unittests to test my changes
• I have added/updated documentation for the changes I am proposing
• I have updated CMakeLists to ensure my code builds
• My code builds across all platforms

[lsawade]

I'll deal with conflict in 3D

[int-ptr-ptr]

@Rohit-Kakodkar
the failed NVIDIA check is the same error I've encountered.

CMake Error at tests/unit-tests/data/dim2/ncmarked_conforming_grid_flat/provenance/CMakeLists.txt:4 (configure_file):

  No such file or directory

Since it can't find the file in a relative path, I set them to absolutes in #1339, which should be a proper fix (at least, I haven't had any issues since).

Edit: nevermind, ncmarked_conforming_grid_flat is the one that you did not add the if(SPECFEMPP_CONFIGURE_TEST) fix to, so your fix might be it. I do both the if statement and absolute-path-inputs in #1339, which we can revert the latter if you don't like it.