Also unset DATA_DIR and CONFIG_FILE during test

Like ASDF_DIR, these two are also likely to be set by user's login
shell, especially the shimmed `bats` (which calls `asdf_cmd()`) command
will eventually set them to user's actual in-use ones, causing conflicts
with the temporary test setup.

test/setup_suite.bash

@@ -3,6 +3,11 @@ setup_suite() {
   # tests fail when it is set to something other than the temp dir.
   unset ASDF_DIR
 
+  # Also unset below variables, because in users shell shimmed commands
+  # (include bats) export them by determining user's real HOME.
+  unset ASDF_DATA_DIR
+  unset ASDF_CONFIG_FILE
+
   # Set an agnostic Git configuration directory to prevent personal
   # configuration from interfering with the tests
   export GIT_CONFIG_GLOBAL=/dev/null