rewriting test_elhmes to assess small numerical changes between x86 & M2

[alaingdl]

all is in the title ! tolerance is 1e-5

[slayoo]

@alaingdl, if not creating a new branch for each PR, you can use the git rebase command to bring this branch in sync with the upstream master branch (which contains a squash commit from your previous PR, but does not contain commits that were squashed). To do it, you can try:

git fetch upstream
git rebase upstream/master
git push -f

This way, this PR will have only the relevant commits.
HTH,
S.