Make Waves2AMR routines deterministic by default

[mbkuhn]

Summary

Regression test "ow_w2a" had been nondeterministic; this was due to the use of certain FFTW approaches that are nondeterministic. This PR allows the user to choose which approach to use and sets the default to a deterministic one.

Pull request type

• [x] Bugfix
• [x] Feature
• [ ] Code style update (formatting, renaming)
• [ ] Refactoring (no functional changes, no api changes)
• [ ] Build related changes
• [ ] Documentation content changes
• [ ] Other (please describe):

Checklist

The following is included:

• [ ] new unit-test(s)
• [ ] new regression test(s)
• [x] documentation for new capability

This PR was tested by running:

• the unit tests
  • [ ] on GPU
  • [x] on CPU
• the regression tests
  • [ ] on GPU
  • [x] on CPU

Additional background

Issue Number: closes #1090