Run libcore tests for m68k

Author: antoyo

.github/workflows/m68k.yml

@@ -25,7 +25,7 @@ jobs:
         commands: [
           "--std-tests",
           # TODO(antoyo): fix those on m68k.
-          #"--test-libcore",
+          "--test-libcore",
           #"--extended-rand-tests",
           #"--extended-regex-example-tests",
           #"--extended-regex-tests",