Update w3srcemd.F90 for considering the contribution of ice scattering of IS1

[Biao-Zhao]

I reported a bug #1386, the current IS1 is not contributing to action density spectrum. Since scattering doesn’t dissipate wave energy, I believe the correct solution is to redistribute the scattered energy to other directions, similar to IS2.

Pull Request Summary

Description

Issue(s) addressed

Commit Message

Check list

• Branch is up to date with the authoritative repository (NOAA-EMC) develop branch.
• Checked the checklist for a developer submitting to develop.
• If a version number update is required, checked the updating version number checklist.
• If a new feature was added, a regression test for testing the new feature is added.

Testing

• How were these changes tested?
• Are the changes covered by regression tests? (If not, why? Do new tests need to be added?)
• Have the matrix regression tests been run (if yes, please note HPC and compiler)?
• Please indicate the expected changes in the regression test output, (Note the list of known non-identical tests.)
• Please provide the summary output of matrix.comp (matrix.Diff.txt, matrixCompFull.txt and matrixCompSummary.txt):