Rename check-names.py to check_names.py

This is necessary to import check_names from other scripts, which
will inevitably happen in the next few commits to implement the equivalent
of `list-identifiers.sh --internal`.

Signed-off-by: Yuto Takano <yuto.takano@arm.com>

tests/scripts/all.sh

@@ -733,7 +733,7 @@ component_check_changelog () {
 
 component_check_names () {
     msg "Check: declared and exported names (builds the library)" # < 3s
-    record_status tests/scripts/check-names.py -v
+    record_status tests/scripts/check_names.py -v
 }
 
 component_check_test_cases () {