test: skip sea tests on riscv64

[sxa]

As documented in #61110 - these tests do not pass on most currently available RISC-V systems.

This matches the approach used for macos/x64 and Linux/ppc64le.

[nodejs-github-bot]

Review requested:

• @nodejs/single-executable

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.52%. Comparing base (4f24aff) to head (6d68db6).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61111      +/-   ##
==========================================
- Coverage   88.53%   88.52%   -0.02%     
==========================================
  Files         703      703              
  Lines      208546   208546              
  Branches    40217    40213       -4     
==========================================
- Hits       184634   184607      -27     
- Misses      15926    15948      +22     
- Partials     7986     7991       +5     

see 43 files with indirect coverage changes

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