Disable cranelift in try builds

Author: tmandry

src/ci/github-actions/jobs.yml

@@ -84,7 +84,7 @@ pr:
 try:
   - image: dist-x86_64-linux
     env:
-      CODEGEN_BACKENDS: llvm,cranelift
+      CODEGEN_BACKENDS: llvm
     <<: *job-linux-16c
 
 # Main CI jobs that have to be green to merge a commit into master