[Chapel Merge] Adjust chpl_launchcmd.py and mandelbrot.prediff

Branch: refs/heads/master
Revision: 9d53743
Author: mppf
Log Message:

Merge pull request #16633 from mppf/fix-launchcmd-mandelbrot

Adjust chpl_launchcmd.py and mandelbrot.prediff

  • adjusted chpl_launchcmd to read into bytes (rather than UTF-8)
    to avoid an error with the mandelbrot test’s binary output
  • adjusted mandelbrot.prediff to save the failed output
    to make these problems easier to find in the future

Resolves a failure with

on XC when chpl_launchmd.py is used.

Reviewed by @lydia-duncan - thanks!

Modified Files:
M test/release/examples/benchmarks/shootout/mandelbrot.prediff
M util/test/chpl_launchcmd.py

Compare: https://github.com/chapel-lang/chapel/compare/80dd82ae187b...9d53743fd5b7