tests: Disable locale.fish on Github Actions

Sometimes hangs with tsan.

Works around #7934.

tests/checks/locale.fish

@@ -1,4 +1,11 @@
 #RUN: %fish -C "set fish %fish" %s
+
+# This hangs when running on github actions with tsan for unknown reasons,
+# see #7934.
+if set -q GITHUB_WORKFLOW
+    exit 0
+end
+
 # A function to display bytes, necessary because GNU and BSD implementations of `od` have different output.
 # We used to use xxd, but it's not available everywhere. See #3797.
 #