[Chapel Merge] Add testing for llvm 11 and 12

Branch: refs/heads/main
Revision: f2da7d4
Author: ronawho
Link: Add testing for llvm 11 and 12 by ronawho · Pull Request #19373 · chapel-lang/chapel · GitHub
Log Message:

Merge pull request #19373 from ronawho/add-llvm-portability-testing

Add testing for llvm 11 and 12

[reviewed by @Maxrimus]

Now that we support multiple versions of llvm, add some explicit testing
for older versions. The current plan is to default to and recommend 13,
but we want some level of testing on 11 and 12 still so add that here.
Currently this just tests release/examples for 11 and 12 on x86 with
comm none, but we may want to add more coverage in the future (more
tests, add gasnet, check on arm too.)

Part of Cray/chapel-private#1031

Modified Files:
A util/cron/test-linux64-llvm11.bash

A util/cron/test-linux64-llvm12.bash

Compare: https://github.com/chapel-lang/chapel/compare/07e7a7ec1df3...f2da7d4dfda1