[Chapel Merge] Fix a prediff of a new-ish GPU test

Branch: refs/heads/main
Revision: 53a1533
Author: e-kayrakli
Link: Fix a prediff of a new-ish GPU test by e-kayrakli · Pull Request #19572 · chapel-lang/chapel · GitHub
Log Message:

Merge pull request #19572 from e-kayrakli/gpu-fix-prediff

Fix a prediff of a new-ish GPU test

This prediff creates the good file, and the main issue with that was that it
wasn't really appending to the output (ie, was using > instead of >>). This
PR fixes that and makes the prediff use sh instead of bash to avoid some
module warning.

[Trivial, not reviewed]

Modified Files:
M test/gpu/native/multiGPU/multiGPU.prediff

Compare: https://github.com/chapel-lang/chapel/compare/fe7ca07eaf93...53a15331857a