Catch node failures in ci

[mcbarton]

When we was experimenting with reducing the initial memory when creating the xeus-cpp tests, the node tests failed to run, but the ci didn't catch it and fail (see https://github.com/compiler-research/xeus-cpp/actions/runs/21941897688/job/63369501220#step:5:182). This PR will attempt to catch these failures, and once they are caught the cmake change will be reverted.

[mcbarton]

Node failures now being caught with set -e (see https://github.com/compiler-research/xeus-cpp/actions/runs/22093639488/job/63844922991?pr=446#step:5:183)

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.25%. Comparing base (b29ea88) to head (173ac09).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #446   +/-   ##
=======================================
  Coverage   81.25%   81.25%           
=======================================
  Files          21       21           
  Lines         864      864           
  Branches       78       78           
=======================================
  Hits          702      702           
  Misses        162      162           

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[mcbarton]

@anutosh491 @SylvainCorlay @vgvassilev pinging for review. Without this change we cannot pick up failures of the Emscripten tests when they are run within node. See the PR description for a recent example where we didn't pick up the failure in the tests running in node (luckily we had the browser tests fail).

[SylvainCorlay]

This looks good to me.