Fix annoying warning when running tests on some macOS machines (#3346)

* don't use LC_ALL of C.UTF-8 on macos when testing

* bump version of racket setup action to version using new NodeJS per GitHub's warnings

.github/workflows/ci-idris2-and-libs.yml

@@ -448,7 +448,7 @@ jobs:
           name: windows-installed-bootstrapped-idris2-chez
           path: ${{ env.IDRIS_PREFIX }}
       - name: Install build dependencies
-        uses: Bogdanp/setup-racket@v1.4
+        uses: Bogdanp/setup-racket@v1.11
         with:
           variant: 'CS'
           version: 'stable'

tests/testutils.sh

@@ -110,7 +110,11 @@ if [ -z "$PREFIX_CHANGED" ] && [ -n "$IDRIS2_PREFIX" ]; then
 fi
 
 # Set the most neutral locale for reproducibility
-export LC_ALL=C.UTF-8
+if [ "$OS" = "darwin" ]; then
+    export LANG=C LC_CTYPE=UTF-8
+else
+    export LC_ALL=C.UTF-8
+fi
 
 # Remove test directory from output
 # Useful for consistency of output between machines